around (adv.)youdaoicibaDictYouDict[around 词源字典]
c. 1300, "in circumference," from phrase on round. Rare before 1600. In sense of "here and there with no fixed direction" it is 1776, American English (properly about). Of time, from 1888. To have been around "gained worldly experience" is from 1927, U.S. colloquial.[around etymology, around origin, 英语词源]
arousal (n.)youdaoicibaDictYouDict
1827, "action of arousing, a being awakened" from arouse + -al (2). Sexual association is from c. 1900.
arouse (v.)youdaoicibaDictYouDict
1590s, "awaken" (transitive), from a- (1) "on" + rouse. Related: Aroused; arousing.
ARPANETyoudaoicibaDictYouDict
acronym from Advanced Research Projects Agency Network, set up in 1969 by a branch of the U.S. Department of Defense in partnership with four universities; acknowledged as "the world's first operational packet switching network" and predecessor of the Internet.
arpeggio (n.)youdaoicibaDictYouDict
1742, from Italian arpeggio, from arpeggiare "to play upon the harp," from arpa "harp," which is of Germanic origin (see harp (n.)). Related: Arpeggiated; arpeggiation.
arr (v.)youdaoicibaDictYouDict
"to growl like a dog," late 15c., imitative. In classical times, the letter R was called littera canina "the dog letter" (Persius).
arrack (n.)youdaoicibaDictYouDict
c. 1600, probably picked up in India, ultimately from Arabic araq, literally "sweat, juice;" used of native liquors in Eastern countries, especially those distilled from fermented sap of coconut palm, sometimes from rice or molasses.
arrahyoudaoicibaDictYouDict
supposedly a characteristic Irish expression of emotion or excitement, 1705.
arraign (v.)youdaoicibaDictYouDict
late 14c., araynen, "to call to account," from Old French araisnier "speak to, address; accuse (in a law court)," from Vulgar Latin *arrationare, from Latin adrationare, from ad- "to" (see ad-) + *rationare, from ratio "argumentation, reckoning, calculation" (see ratio). Sense of "to call up on a criminal charge" is c. 1400. The excrescent -g- is a 16c. overcorrection based on reign, etc. Related: Arraigned; arraigning.
arraignment (n.)youdaoicibaDictYouDict
mid-15c., from Old French araisnement, from araisnier (see arraign).
arrange (v.)youdaoicibaDictYouDict
late 14c., "draw up a line of battle," from Old French arengier (12c.), from a- "to" (see ad-) + rangier "set in a row" (Modern French ranger), from rang "rank," from Frankish *hring (see rank (n.)).

A rare word until the meaning generalized to "to place things in order" c. 1780-1800. Musical sense of "adapt for other instruments or voices" is from 1808. Related: Arranged; arranging. Arranged marriage attested from 1854.
arrangement (n.)youdaoicibaDictYouDict
1727, from French arrangement, from arranger "arrange" (see arrange).
arrant (adj.)youdaoicibaDictYouDict
late 14c., variant of errant (q.v.); at first merely derogatory, "wandering, vagrant;" then (1540s) acquiring a meaning "thoroughgoing, downright, notorious."
arras (n.)youdaoicibaDictYouDict
"pictured tapestry," late 14c., from Anglo-French draps d'arras, from Arras, city in France where pictured tapestries were made, from Latin Atrebates, name of a tribe of the Belgae who inhabited the Artois region; probably literally "inhabitants," from a Celtic trebu "tribe."
array (v.)youdaoicibaDictYouDict
early 14c., from stem of Old French areer "to put in order," from Vulgar Latin *ar-redare (source of Italian arredare), from Latin ad- "to" (see ad-) + Frankish *ræd- "ready" or some cognate Germanic source, from Proto-Germanic *raidjan "to place in order" (cognates: Gothic garadis, Old English geræde "ready;" see ready (adj.)). Related: Arrayed; arraying.
array (n.)youdaoicibaDictYouDict
mid-14c., "order, arrangement," from Anglo-French arrai, Old French aroi, from areer (see array (v.)).
arrearyoudaoicibaDictYouDict
c. 1300, "at a disadvantage;" mid-14c., "in times past;" late 14c., "in or to the rear;" see arrears. Meaning "behind in duties or payments" is from 1620s.
arrearage (n.)youdaoicibaDictYouDict
"unpaid debt," early 14c., from Old French arierage "detriment, prejudice (in a legal sense)" (Modern French arrérage), from arere "behind;" see arrears.
arrears (n.)youdaoicibaDictYouDict
mid-14c., "in times past," from Old French ariere "behind, backward," from Vulgar Latin *ad retro, from Latin ad "to" (see ad-) + retro "behind" (see retro-). Meaning "balance due" dates from early 15c.; phrase in arrears first recorded 1610s, but in arrearages is from late 14c.
arrest (v.)youdaoicibaDictYouDict
"to cause to stop," also "to detain legally," late 14c., from Old French arester "to stay, stop" (Modern French arrêter), from Vulgar Latin *arrestare (source of Italian arrestare, Spanish and Portuguese arrestar), from Latin ad- "to" (see ad-) + restare "to stop, remain behind, stay back" (see rest (n.2)). Figurative sense of "to catch and hold" (the attention, etc.) is from 1814.