Etymology dictionary
archivist (n.) — armistice (n.)
archivist (n.)
"a keeper of archives or records," 1753, a native formation or else from Medieval Latin or Italian archivista or French archiviste (see archives + -ist).
archivolt (n.)
ornamental molding on the face of an arch, 1731, from Italian archivolto, from volta, volto "arch, vault" (see vault (n.1)). The archi- here perhaps meant originally "chief."
archon (n.)
one of the nine chief magistrates of ancient Athens, 1650s, from Greek arkhon "ruler, commander, chief, captain," noun use of present participle of arkhein "be the first," thence "to begin, begin from or with, make preparation for;" also "to rule, lead the way, govern, rule over, be leader of," a word of uncertain origin.
arch-rival (n.)
also archrival, "chief opponent or competitor for the same goal," by 1805, from arch- + rival (n.).
arch-villain (n.)
"a desperate, confirmed villain," c. 1600, from arch- + villain.
archway (n.)
"entrance or passageway under an arch or vault," also arch-way, 1788, from arch (n.) + way (n.).
arc-light (n.)
"light produced by an electric arc," 1871, from arc (n.) + light (n.). Related: Arc-lamp.
arctic (adj.)
late 14c., artik, "of or pertaining to the north pole of the heavens," from Old French artique and directly from Medieval Latin articus, from Latin arcticus, from Greek arktikos "of the north," literally "of the (constellation) Bear," from arktos "bear;" also "Ursa Major; the region of the north," the Bear being the best-known northern circumpolar constellation.
This is from *rkto-, the usual Indo-European root for "bear" (source also of Avestan aresho, Armenian arj, Albanian ari, Latin ursus, Welsh arth). For speculation on why Germanic lost the word, see bear (n.). The -c- was restored from 1550s.
It is attested from early 15c. as "northern;" from 1660s as "cold, frigid." As a noun, with capital A-, "the northern polar regions," from 1560s.
Arctic Circle
1550s in astronomy, in reference to a celestial circle, a line around the sky which, in any location, bounds the stars which are ever-visible from that latitude (in the Northern Hemisphere its center point is the celestial north pole); the concept goes back to the ancient Greeks, for whom this set of constellations included most prominently the two bears (arktoi), hence the name for the circle (see arctic). In Middle English it was the north cercle (late 14c.).
In geography, from 1620s as "the circle roughly 66 degrees 32 minutes north of the equator" (based on obliquity of the ecliptic of 23 degrees 28 minutes), marking the southern extremity of the polar day, when the sun at least theoretically passes the north point without setting on at least one summer day and does not rise on at least one winter one.
Arcturus
late 14c., orange bright star in the constellation Bootes (also used of the whole constellation), from Latin Arcturus, from Greek Arktouros, literally "guardian of the bear" (the bright star was anciently associated with nearby Ursa Major, the "Big Dipper," which it seems to follow across the sky). For first element see arctic; second element is Greek ouros "watcher, guardian, ward" (from PIE root *wer- (3) "perceive, watch out for"). It is fourth-brightest of the fixed stars. The double nature of the great bear/oxen wagon (see Charles's Wain) has given two different names to the constellation that follows it: Arktouros "bear-ward" and Bootes, "cow-herd."
Arcturus in the Bible (Job ix.9 and xxxviii.32) is a mistranslation by Jerome (continued in KJV) of Hebrew 'Ayish, which refers to what we see as the "bowl" of the Big Dipper. In Israel and Arabia, the seven stars of the Great Bear seem to have been a bier (the "bowl") followed by three mourners. In the Septuagint it was translated as Pleiada, which is equally incorrect.
arcuate (adj.)
"bent like a bow," 1620s, from Latin arcuatus "bow-like, arched," past participle of arcuare "to bend like a bow," from arcus "a bow" (see arc (n.)). Related: Arcuration.
-ard
also -art, from Old French -ard, -art, from German -hard, -hart "hardy," forming the second element in many personal names, often used as an intensifier, but in Middle High German and Dutch used as a pejorative element in common nouns, and thus passing into Middle English in bastard, coward, blaffard ("one who stammers"), tailard "one who has a tail" (a term of abuse), etc.
It thus became a living element in English, as in buzzard, drunkard. The German element is from Proto-Germanic *-hart/*-hard "bold, hardy" (from PIE root *kar- "hard").
ardency (n.)
1540s, "warmth of feeling, desire," from ardent + -cy. A figurative sense, the literal meaning "intensity of heat" is attested from 1630s.
ardent (adj.)
early 14c., ardaunt, specifically of alcoholic distillates, brandy, etc., "flammable," from Old French ardant "burning, hot; zealous" (13c.), from Latin ardentem (nominative ardens) "glowing, fiery, hot, ablaze," also used figuratively of passions, present participle of ardere "to burn" (from PIE root *as- "to burn, glow").
The figurative sense ("burning with passions, desire, etc.") is from late 14c.; the general etymological sense of "burning, parching" (c. 1400) remains rare. Ardent spirits (late 15c.) retains the oldest English meaning, but the term now, if used at all, probably is felt in a figurative, causative sense. Related: Ardently.
ardor (n.)
"heat of passion or desire," mid-15c., ardour, from Old French ardure "heat, glow; inflammation; passion" (12c., Modern French ardeur), from Latin ardorem (nominative ardor) "a flame, fire, burning, heat;" also of feelings, etc., "eagerness, zeal," from ardere "to burn" (from PIE root *as- "to burn, glow"). In Middle English used of base passions; since Milton's time of noble ones.
ardour (n.)
chiefly British English spelling of ardor (q.v.); for spelling, see -or.
arduous (adj.)
1530s, "hard to accomplish, difficult to do, attended with much labor," from Latin arduus "high, steep," also figuratively, "difficult, hard to reach" (from PIE root *eredh- "high;" for which see ortho-). The literal sense of "high, steep, difficult to climb" is attested in English from 1709. Related: Arduously; arduousness.
ardurous (adj.)
"full of ardor," 1770, perhaps a variant of arduous with overtones of ardor. Useful only to poets, and, as it is first attested in Chatterton, perhaps a faux medievalism.
area (n.)
1530s, "vacant piece of ground," from Latin area "level ground, open space," used of building sites, playgrounds, threshing floors, etc.; which is of uncertain origin. Perhaps an irregular derivation from arere "to become dry" (see arid), on notion of "bare space cleared by burning." The generic sense of "any particular amount of surface (whether open or not) contained within any set of limits" is from 1560s. Area code in the North American telephone systems is attested from 1959.
areal (adj.)
"pertaining to an area," 1670s, from Latin arealis, from area "level ground, open space" (see area).
area-way (n.)
"passageway between buildings," 1850, from area + way (n.).
arena (n.)
1620s, "place of combat," from Latin harena "place of combat, enclosed space in the middle of Roman amphitheaters," originally "sand, sandy place" (source also of Spanish arena, Italian rena, French arène "sand"), a word of uncertain origin, perhaps from Etruscan. The central stages of Roman amphitheaters were strewn with sand to soak up the blood. Figuratively, "scene of contest of any kind" by 1814.
arenaceous (adj.)
1640s, "sandy," from Latin arenaceus, harenaceus, from harena "sand, sandy place" (see arena). The figurative sense of "dry" is attested from 1870.
aren't
1670s, contraction of are not, originally also written are'n't and generally so into early 19c.
areolas (n.)
nativized plural of areola (q.v.), which has its proper plural in areolae (see -ae).
areola (n.)
"colored circle around a nipple" (areola papillaris), 1706, from Latin areola, literally "small area," diminutive of area (see area). Introduced in this sense 1605 by Swiss anatomist and botanist Caspar Bauhin. The word also is used in other anatomical senses. Related: Areolar.
Areopagite (n.)
"member of the Areopagus court," late 14c. (Acts xvii.34); see Areopagus + -ite (1). Related: Areopagitic; Areopagitical.
Areopagus
1640s, Greek, Areios pagos "the hill of Ares," west of the Acropolis in Athens, where the highest judicial court sat. The second element is from pagos "pinnacle, cliff, rocky hill," related to pegnunai "to fasten, coagulate" (from PIE root *pag- "to fasten"). The sense was extended to any important tribunal.
arete (n.1)
"sharp crest of a mountain," 1862, from Swiss French arête, Old French areste, from Latin arista "ear of grain, the top of an ear," in Medieval Latin also "backbone of a fish; exterior angle of a house," which perhaps is of Etruscan origin. The figure is of something jagged.
arete (n.2)
important concept in Greek philosophy, from Greek aretē "rank, nobility, moral virtue, excellence," especially of manly qualities; literally "that which is good," a word of uncertain origin.
*arg-
Proto-Indo-European root meaning "to shine; white," hence "silver" as the shining or white metal.
It forms all or part of: argent; Argentina; argentine; Argo; argue; Argus; hydrargyrum; litharge.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit rajata-, Avestan erezata-, Old Persian ardata-, Armenian arcat, Greek arguron, Latin argentum, Old Irish argat, Breton arc'hant "silver;" Sanskrit arjuna- "white, shining;" Hittite harki- "white;" Greek argos "white."
argent (n.)
early 15c., "silver, silver coin," from Old French argent "silver, silver money; quicksilver" (11c.), from Latin argentum "silver, silver work, silver money," from PIE *arg-ent-, suffixed form of root *arg- "to shine; white," thus "silver" as "the shining or white metal." It was earlier in English in the sense of "quicksilver, the metal mercury" (c. 1300); the adjective sense "silver-colored" is from late 15c.
argentine (adj.)
mid-15c., "silver-colored;" c. 1500, "of or resembling silver," from Old French argentin (12c.), from Latin argentinus "of silver," from argentum "silver," from PIE root *arg- "to shine; white," hence "silver" as the shining or white metal.
Argentina
South American nation, from Latin argentinus "of silver," from PIE root *arg- "to shine; white," hence "silver" as the shining or white metal. It is a Latinized form of (Rio) de la Plata "Silver River," from Spanish plata "silver" (see plate (n.)).
Argive (adj.)
"of Argos," ancient Peloponnesian city portrayed by Homer as the most powerful in Greece, hence, especially in Homeric usage, "the Greeks," as a byword for Achaean, 1520s, from Latin Argivus, from Greek Argeios "of Argos." Related: Argives.
argle (v.)
1580s "to argue obstinately, wrangle," "prob. a popular perversion of argue, or confusion of that word with haggle" [OED]. Reduplicated form argle-bargle is from 1822 (sometimes argy-bargy, 1857); As a noun, "wrangling" from 1861.
Argo
name of the ship in which Jason and his 54 heroic companions sought the Fleece in Colchis on the Euxine Sea, in Greek, literally "The Swift," from argos "swift" (adj.), an epithet, literally "shining, bright" (from PIE root *arg- "to shine; white"), "because all swift motion causes a kind of glancing or flickering light" [Liddell & Scott]. Related: Argean.
argon (n.)
chemical element, 1894, Modern Latin, from Greek argon, neuter of argos "lazy, idle, not working the ground, living without labor," from a- "without" (see a- (3)) + ergon "work" (from PIE root *werg- "to do"). So called by its discoverers, Baron Rayleigh and Sir William Ramsay, for its inert qualities. They described it as "most astonishingly indifferent."
Argonaut (n.)
"sailor of the Argo," 1580s (Argonautic (n.)), from Argo + Greek nautēs "sailor" (from PIE root *nau- "boat"). Adventurers in the California Gold Rush of 1848 were called argonauts (because they sought the golden fleece) by those who stayed home.
argosy (n.)
1570s, "large merchant vessel carrying rich freight," from Italian (nave) Ragusea "(vessel) of Ragusa," maritime city on the Dalmatian coast of the Adriatic (modern Dubrovnik in Croatia). Their large merchant ships brought rich Eastern goods to 16c. England. The city name sometimes was Aragouse or Arragosa in 16c. English. Figurative use from 1620s.
argot (n.)
1860, from French argot (17c.) "the jargon of Paris rogues and thieves" (for purposes of disguise and concealment), earlier "the company of beggars," from French argot, "group of beggars," a word of unknown origin.
Gamillscheg suggests a connection to Old French argoter "to cut off the stubs left in pruning," with a connecting sense of "to get a grip on." The best English equivalent is perhaps cant. The German equivalent is Rotwelsch, literally "Red Welsh," but the first element of that might be connected with Middle High German rot "beggar." Compare pedlar's French (1520s) "language of thieves and vagabonds."
argue (v.)
c. 1300, "to make reasoned statements to prove or refute a proposition," from Old French arguer "maintain an opinion or view; harry, reproach, accuse, blame" (12c.), ultimately from Latin arguere "make clear, make known, prove, declare, demonstrate" (from a suffixed form of PIE root *arg- "to shine; white"). The transmission to French might be via arguere in a Medieval Latin sense of "to argue," or from Latin argutare "to prattle, prate," frequentative of arguere.
De Vaan says arguere is probably "a denominative verb 'to make bright, enlighten' to an adj. *argu- 'bright' as continued in argutus and outside Italic." He cites a closely similar formation in Hittite arkuuae- "to make a plea." The meaning "to oppose, dispute, contend in argument" is from late 14c. Related: Argued; arguing.
Argus
hundred-eyed giant of Greek mythology, late 14c., from Latin, from Greek Argos, literally "the bright one," from argos "shining, bright" (from PIE root *arg- "to shine; white"). His epithet was Panoptes "all-eyes." After his death, Hera transferred his eyes to the peacock's tail. The name also is used in the figurative sense of "very vigilant person."
arguably (adv.)
"as may be shown by argument," 1871, from arguable + -ly (2).
arguable (adj.)
"capable of being argued," 1610s, from argue + -able.
arguendo
"in the course of argument," 1817, courtroom Latin, from Medieval Latin ablative of arguendum, gerundive of arguere "to argue" (see argue).
arguer (n.)
"one who argues or is fond of arguing," late 14c., agent noun from argue (v.).
argufy (v.)
"to argue for the sake of controversy, wrangle, worry with arguments," 1751, colloquial, from argue + -fy. Compare speechify.
argumentation (n.)
mid-15c., "presentation of formal arguments," from Old French argumentacion (14c.), from Latin argumentationem (nominative argumentatio) "the bringing forth of a proof," noun of action from past-participle stem of argumentari "adduce proof, draw a conclusion," from argumentum (see argument). The meaning "debate, wrangling, argument back and forth" is from 1530s.
argument (n.)
early 14c., "statements and reasoning in support of a proposition or causing belief in a doubtful matter," from Old French arguement "reasoning, opinion; accusation, charge" (13c.), from Latin argumentum "a logical argument; evidence, ground, support, proof," from arguere "make clear, make known, prove" (see argue). The sense in English passed through "subject of contention" (1590s) to "a quarrel" (by 1911), a sense formerly attached to argumentation.
argumentative (adj.)
mid-15c., "pertaining to arguments," from Old French argumentatif "able to argue or reason well," or directly from Medieval Latin argumentat-, past-participle stem of argumentari "adduce proof, draw a conclusion," from argumentum (see argument) + -ive. The meaning "fond of arguing" is recorded from 1660s. Related: Argumentatively; argumentativeness.
Argyle (n.)
"diamond-shaped pattern of two or more colors in fabric," said to be so called from similarity to tartans worn by Campbell clan of Argyll, Scotland. The place name is literally "land of the Gaels," with first element from Old Irish airer "country." Argyle socks is from 1935.
Aries
zodiacal constellation usually identified as "the Ram," late Old English, from Latin aries "ram" (related to arietare "to butt"), from a PIE root meaning "spring, jump" (source also of Lithuanian ėrytis, Old Church Slavonic jarici, Armenian oroj "lamb;" Greek eriphos, Old Irish heirp"kid").
The meaning "person born under the sign of Aries" is from 1894; they also have been called Arians (1917).
-ary
adjective and noun word-forming element, in most cases from Latin -arius, -aria, -arium "connected with, pertaining to; the man engaged in," from PIE relational adjective suffix *-yo- "of or belonging to." The neuter of the adjectives in Latin also were often used as nouns (solarium "sundial," vivarium, honorarium, etc.). It appears in words borrowed from Latin in Middle English. In later borrowings from Latin to French, it became -aire and passed into Middle English as -arie, subsequently -ary.
aria (n.)
"melody for a single voice," 1775, from Italian aria, literally "air" (see air (n.1)).
Ariadne
in Greek mythology, the daughter of Minos, king of Crete, abducted by Theseus; from Greek Ariadnē, a name of uncertain etymology, but probably Pre-Greek. Beekes points out that "An IE etymology is improbable for a Cretan goddess."
Arianism (n.)
"the doctrine of the Arians," who held that Christ was created by and subordinate to the Father, c. 1600, from Arian (q.v.) + -ism.
Arian (adj.)
late 14c., Arrian, "adhering to the doctrines of Arius," from Late Latin Arianus, "pertaining to the doctrines of Arius," priest in Alexandria early 4c., who posed the question of Christ's nature in terms which appeared to debase the Savior's relation to God (denial of consubstantiation). Besides taking an abstract view of Christ's nature, he reaffirmed man's capacity for perfection. The doctrines were condemned at Nice, 325, but the dissension was widespread and split the Church for about a century during the crucial time of barbarian conversions. The name is Greek, literally "warlike, of Ares."
arid (adj.)
1650s, "dry, parched, without moisture," from French aride "dry" (15c.) or directly from Latin aridus "dry, arid, parched," from arere "to be dry" (from PIE root *as- "to burn, glow"). The figurative sense of "uninteresting" is from 1827. Related: Aridly; aridness.
aridity (n.)
"dryness, want of moisture," 1590s, from French aridité or directly from Latin ariditatem (nominative ariditas) "dryness," from aridus "dry" (see arid). Used figuratively from 1690s; the Latin word was used figuratively of unadorned styles as well as stingy men.
Ariel
1382, in the Wycliffe Bible, a word taken untranslated from the Vulgate, from Greek ariel (Septuagint), from Hebrew ariel; in later Bibles, translated as "altar."
As the name of a species of gazelle found in the Middle East, 1832, from Arabic aryil, variant of ayyil "stag." The Uranian satellite was discovered in 1851.
aright (adv.)
"in a correct way, rightly, without error or fault," Old English ariht, from a- (1) "of" + right (adj.1).
aril (n.)
"accessory covering of seeds," 1783, from Modern Latin arillus, from Medieval Latin arilli, Spanish arillos "dried grapes, raisins," from Latin aridus "dry" (see arid).
Arimasp (n.)
1570s, from Latin Arimaspi (plural), from Greek Arimaspoi, mythical race of one-eyed people in Northern Europe believed in antiquity to have carried off a hoard of gold which was under guardianship of griffins. The name is said to be Scythian for "one-eyed." Related: Arimaspian.
arioso
in music, "melodious, in a melodious way," 1742, from Italian arioso "like an aria," from aria "melody" (see aria). Distinguished from recitative.
arising (n.)
verbal noun from arise (v.). Replaced in most senses by rising (n.).
arise (v.)
Middle English arisen, from Old English arisan "to get up from sitting, kneeling, or lying; have a beginning, come into being or action, spring from, originate; spring up, ascend" (cognate with Old Saxon arisan, Gothic urreisan), from a- (1) "of" + rise (v.). Mostly replaced by rise except in reference to circumstances; formerly the choice between the two often was made merely for the sake of rhythm.
arisen
past participle of arise (q.v.).
aristarchy (n.)
"government by the best men; body of worthies constituting a government," 1889, from Greek aristarkhia, from aristos "best" (see aristo-) + -arkhia "government" (see -archy).
aristo-
word-forming element meaning "best," also "of the aristocracy," from Greek aristos "best of its kind, noblest, bravest, most virtuous" (of persons, animals, things), originally "most fitting," from PIE *ar(ə)-isto-, suffixed (superlative) form of root *ar- "to fit together."
aristocracy (n.)
1560s, "government by those who are the best citizens," from French aristocracie (Modern French aristocratie), from Late Latin aristocratia, from Greek aristokratia "government or rule of the best; an aristocracy," from aristos "best of its kind, noblest, bravest, most virtuous" (see aristo-) + abstract noun from kratos "rule, power" (see -cracy).
In early use contrasted with monarchy; after the French and American revolutions, with democracy. The meaning "rule by a privileged class, oligarchy, government by those distinguished by rank and wealth" (best-born or best-favored by fortune) is from 1570s and became paramount 17c. Hence the meaning "patrician order, the class of hereditary nobles" (1610s), and, generally, that of "persons notably superior in any way, taken collectively" (1650s).
aristocratic (adj.)
c. 1600, "pertaining to aristocracy," from French aristocratique, from Latinized form of Greek aristokratikos "belonging to the rule of the best," from aristokratia (see aristocracy). The meaning "grand, stylish, befitting the nobility" is from 1845. Related: Aristocratical (1580s); aristocratically.
aristocrat (n.)
"one having high rank in a community," also "advocate of aristocratic government," 1789, from French aristocrate, a word of the Revolution, a back-formation from aristocratie (see aristocracy).
aristology (n.)
"science of dining," 1835, with -ology "study of" + Greek ariston "breakfast, the morning meal" (later "the mid-day meal"), a contraction of a locative ari- (see ere) + *ed- "to eat" (see eat). Related: Aristological; aristologist.
Aristotelian (adj.)
also Aristotelean, c. 1600, of or pertaining to the person or teachings of Greek philosopher Aristotle (384-322 B.C.E.), the father of logic.
arithmancy (n.)
"divination by numbers," 1570s, from Greek arithmos "number" (see arithmetic) + -mancy "divination by means of." Alternative arithmomancy is recorded from 1620s.
arithmetic (n.)
"art of computation, the most elementary branch of mathematics," mid-13c., arsmetike, from Old French arsmetique (12c.), from Latin arithmetica, from Greek arithmetikē (tekhnē) "(the) counting (art)," fem. of arithmetikos "of or for reckoning, arithmetical," from arithmos "number, counting, amount" (from PIE *erei-dhmo-, suffixed variant form of root *re- "to reason, count").
The form arsmetrik was based on folk-etymology derivation from Medieval Latin ars metrica; the spelling was corrected early 16c. in English (though arsmetry is attested from 1590s) and French. The native formation in Old English was tælcræft, literally "tell-craft."
arithmetical (adj.)
"pertaining to or according to the rules of arithemetic," 1540s; see arithmetic + -al (1). In modern use, opposed to geometrical. Related: Arithmetically (late 15c.).
arithmocracy (n.)
"rule by numerical majority," 1850, from Greek arithmos "number, counting, amount" (see arithmetic) + -cracy "rule or government by." Related: Arithmocratic; arithmocratical.
arithmomania (n.)
"compulsive desire to count objects and make calculations," 1884, from French arithmomanie, from Greek arithmos "number, counting, amount" (see arithmetic) + French -manie (see mania). Related: Arithmomaniac.
Arizona
1861, originally as the name of a breakaway Confederate region of southern New Mexico; later applied to a U.S. territory organized in 1863 roughly along the lines of the modern state and admitted in 1912. From Spanish Arizonac, which is probably from a local name among the O'odham (Piman) people meaning "having a little spring." An alternative theory is that it derives from Basque arizonak "good oaks."
ark (n.)
Middle English arke, from Old English earc, Old Northumbrian arc, mainly meaning Noah's, but also the Ark of the Covenant (the coffer holding the tables of the law in the sanctum sanctorum), from Latin arca "large box, chest" (see arcane), the word used in the Vulgate. It also was borrowed in Old High German (arahha, Modern German Arche).
In general as "a coffer, a box" by late 12c. Also sometimes in Middle English "the breast or chest as the seat of emotions." From the Noachian sense comes the extended meaning "place of refuge" (17c.). As the name of a type of ship or boat, from late 15c. In 19c. U.S., especially a large, flat-bottomed river boat to move produce, livestock, etc. to market.
Arkansas
organized as a U.S. territory 1819, admitted as a state 1836; it was named for the Arkansas River, which was named for a Siouan tribe.
The silent final -s, perhaps originally from the French pronunciation, was made official in 1881 by an act of the state legislature.
armed (adj.)
"equipped for battle," early 13c., past-participle adjective from arm (v.).
armful (n.)
"as much as the arms can hold; what one can embrace," 1570s, from arm (n.1) + -ful.
arm (n.1)
[upper limb of the human body], Middle English arm, from Old English earm, from Proto-Germanic *armaz (source also of Old Saxon, Danish, Swedish, Middle Dutch, German arm, Old Norse armr, Old Frisian erm), from PIE root *ar- "to fit together" (source also of Sanskrit irmah "arm," Greek arthron "a joint," Latin armus "shoulder").
Arm of the sea was in Old English. Arm-twister "powerful persuader" is from 1915. Arm-wrestling is from 1899.
arm (n.2)
[weapon], c. 1300, armes (plural) "weapons of a warrior," from Old French armes (plural), "arms, weapons; war, warfare" (11c.), from Latin arma "weapons" (including armor), literally "tools, implements (of war)," from PIE *ar(ə)mo-, suffixed form of root *ar- "to fit together." The notion seems to be "that which is fitted together." Compare arm (n.1).
The meaning "branch of military service" is from 1798, hence "branch of any organization" (by 1952). The meaning "heraldic insignia" (in coat of arms, etc.) is early 14c., from a use in Old French; originally they were borne on shields of fully armed knights or barons. To be up in arms figuratively is from 1704; to bear arms "do military service" is by 1640s.
arm (v.)
"furnish with weapons," c. 1200, from Old French armer "provide weapons to; take up arms," or directly from Latin armare "furnish with arms," from arma "weapons," literally "tools, implements" of war (see arm (n.2)). The intransitive sense of "provide oneself with weapons" in English is from c. 1400. Related: Armed; arming.
armada (n.)
"fleet of warships," 1530s (armado), from Spanish armada "an armed force," from Medieval Latin armata "armed force" (see army). The current form of the English word is from 1590s. The fleet sent by Philip II of Spain against England in 1588 was called the Spanish Armada by 1613, the Invincible Armada by 1632, presumably with more or less of irony.
armadillo (n.)
burrowing mammal of the American tropics, 1570s, from Spanish armadillo, diminutive of armado "armored," from Latin armatus, past participle of armare "to arm, furnish with weapons," from arma "weapons" (including defensive armor), literally "tools, implements (of war);" see arm (n.2). The animal is so called for its hard, plated shell.
Armageddon (n.)
"cataclysmic final conflict," 1811, figurative use of the place-name in Revelation xvi.16, the site of the great and final conflict, from Hebrew Har Megiddon "Mount of Megiddo," a city in central Palestine, site of important Israelite battles.
armament (n.)
1650s, "naval force equipped for war," from Latin armamentum "implement," from Latin armare "to arm, furnish with weapons" from arma "weapons" (including defensive armor), literally "tools, implements (of war);" see arm (n.2). The meaning "process of equipping for war" is from 1813.
armamentarium (n.)
"an armory," 1874, Latin, literally "little arsenal," from armamenta "implements, weapons" (see armament). Earlier Englished as armamentary (1731).
armature (n.)
c. 1400, "an armed force," from Latin armatura "armor, equipment," from armatus, past participle of armare "to arm, furnish with weapons" from arma "weapons," literally "tools, implements (of war);" see arm (n.2). The meaning "armor" is mid-15c.; that of "protective covering of a plant or animal" is from 1660s. The electromagnetic sense is from 1835.
arm-band (n.)
"band or bracelet for the arm," by 1782; see from arm (n.1) + band (n.1).
armchair (n.)
also arm-chair, "chair with rests for the elbows," 1630s, from arm (n.1) + chair (n.). Another old name for it was elbow-chair (1650s). The adjectival sense, in reference to "criticism of matters in which the critic takes no active part," is from 1879.
Armenia
late 14c., a place-name traced to 521 C.E., of uncertain origin. Armenian is from 1590s as "a native of Armenia;" as the name of the Indo-European language spoken there, by 1718; as an adjective, by 1727.
army (n.)
late 14c., armee, "armed expedition," from Old French armée "armed troop, armed expedition" (14c.), from Medieval Latin armata "armed force," from Latin armata, fem. of armatus "armed, equipped, in arms," as a noun, "armed men, soldiers," past participle of armare "to arm," literally "act of arming," related to arma "tools, arms" (see arm (n.2)).
Originally used of expeditions on sea or land; the restriction to "land force" is by late 18c. The transferred meaning "host, multitude" is by c. 1500. The meaning "body of men trained and equipped for war" is from 1550s.
The Old English words were here (still preserved in derivatives such as harrier; see harry (v.)), from Proto-Germanic *harjan, from PIE *korio- "people, crowd;" and fierd, with an original sense of "expedition," from Proto-Germanic *farthi-, related to faran "travel" (see fare (v.)). In spite of etymology, in the Anglo-Saxon Chronicle here generally meant "invading Vikings" and fierd was used for the local militias raised to fight them. Army-ant is from 1863, so called for marching in immense numbers.
armilla (n.)
1706, "bracelet," from Latin armilla "bracelet, armlet, arm ring," from armus "shoulder, upper arm" (from PIE root *ar- "to fit together"). With specialized senses in anatomy, machinery, etc. Related: Armillary "arranged in rings or circles."
Arminian (adj.)
1610s in reference to a Protestant sect, from Arminius, the Latinized form of the name of James Harmensen (1560-1609), Dutch Protestant theologian who opposed Calvin, especially on the question of predestination. His ideas were denounced at the Synod of Dort, but nonetheless spread in the Reformed churches. As a noun from 1610s. Related: Arminianism.
armistice (n.)
"temporary suspension of hostilities by agreement of the parties," 1707, from French armistice (1680s), coined on the model of Latin solstitium (see solstice), etc., from Latin arma "arms" (see arm (n.2)) + -stitium (used only in compounds), from PIE *ste-ti-, suffixed form of root *sta- "to stand, make or be firm."
The word is attested in English from 1660s in the Latin form armistitium. German Waffenstillstand is a loan-translation from French. Armistice Day (1919) commemorated the end of the Great War of 1914-18 on Nov. 11, 1918, and memorialized the dead in that war. In Britain, after World War II, it merged with Remembrance Day. In U.S. (which had already a Memorial Day for the dead), Armistice Day became a national holiday in 1926; and in 1954, it was expanded to also honor living World War II and Korean War veterans and was re-dubbed Veterans Day.