assiduous (adj.) Look up assiduous at Dictionary.com
1530s, from Latin assiduus "attending; continually present, incessant; busy; constant," from assidere/adsidere "to sit down to, sit by" (thus "be constantly occupied" at one's work); from ad "to" (see ad-) + sedere "to sit," from PIE root *sed- (1) "to sit." The word acquired a taint of "servility" in 18c. Related: Assiduously; assiduousness.
assiento (n.) Look up assiento at Dictionary.com
1714, "contract between the King of Spain and another power," especially that made at the Peace of Utrecht, 1713, with Great Britain for furnishing African slaves to the Spanish colonies in the Americas (abrogated in 1750), from Spanish asiento, formerly assiento "a compact or treaty; a seat in court, a seat," from asentar/assentar "to adjust, settle, establish," literally "to place on a seat," from a sentar, from Latin ad "to" (see ad-) + sedens, present participle of sedere "to sit," from PIE root *sed- (1) "to sit."
assify (v.) Look up assify at Dictionary.com
"to make an ass of" (someone), 1804, from ass (n.1) + -ify. Related: Assified; assification (1823).
assign (v.) Look up assign at Dictionary.com
c. 1300, "to transfer, convey, bequeath (property); appoint (to someone a task to be done); order, direct (someone to do something); fix, settle, determine; appoint or set (a time); indicate, point out," from Old French assiginer "assign, set (a date, etc.); appoint legally; allot" (13c.), from Latin assignare/adsignare "to mark out, to allot by sign, assign, award," from ad "to" (see ad-) + signare "make a sign," from signum "identifying mark, sign" (see sign (n.)). Original use was in legal transferences of personal property. Related: Assigned; assigning.
assignat (n.) Look up assignat at Dictionary.com
paper money of the French Revolution, 1790, from French assignat, from Latin assignatus, past participle of assignare/adsignare (see assign). Based on the security of confiscated Church lands, it was over-issued and the value quickly deteriorated.
assignation (n.) Look up assignation at Dictionary.com
early 14c., "appointment by authority," from Old French assignacion (14c., Modern French assignation), from Latin assignationem (nominative assignatio) "an assigning, allotment," noun of action from past participle stem of assignare/adsignare "to mark out, to allot by sign, assign, award," from ad "to" (see ad-) + signare "make a sign," from signum "identifying mark, sign" (see sign (n.)).

Meaning "action of legally transferring" (a right or property) is from 1570s; that of "a meeting by arrangement, tryst" is from 1650s, especially for a love-affair; assignation-house (1849) was an old euphemism for "brothel."
assignee (n.) Look up assignee at Dictionary.com
early 15c., "one who is appointed to act for another," from Old French assigne, past participle of assignier "appoint legally" (see assign).
assignment (n.) Look up assignment at Dictionary.com
late 14c., "an order, request, directive," from Old French assignement "(legal) assignment (of dower, etc.)," from Late Latin assignamentum, noun of action from Latin assignare/adsignare "to allot, assign, award" (see assign). Meaning "appointment to office" is mid-15c.; that of "a task assigned (to someone), commission" is by 1848.
assimilable (adj.) Look up assimilable at Dictionary.com
1660s, from Latin assimilabilis, from assimilare "to make like; assume the form of" (see assimilate). Related: Assimilability.
assimilate (v.) Look up assimilate at Dictionary.com
early 15c., in physiology, "absorb into and make part of the body," from Latin assimilatus, past participle of assimilare, assimulare "to make like, copy, imitate, assume the form of; feign, pretend," from assimilated form of ad "to" (see ad-) + simulare "make similar," from similis "like, resembling, of the same kind" (see similar).

Meaning "make alike, cause to resemble," and intransitive sense "become incorporated into" are from 1620s. In linguistics, "bring into accordance or agreement in speech," from 1854. Related: Assimilated; assimilating.
assimilation (n.) Look up assimilation at Dictionary.com
early 15c., "act of assimilating," in reference to the body's use of nutrition, from Old French assimilacion, from Latin assimilationem (nominative assimilatio) "likeness, similarity," noun of action from past participle stem of assimilare "to make like" (see assimilate). Meaning "process of becoming alike or identical, conversion into a similar substance" is from 1620s. Figurative use from 1790. Psychological sense is from 1855.
assimilationist (n.) Look up assimilationist at Dictionary.com
"one who advocates racial or ethnic integration," 1900, originally in reference to Hawaii and possessions obtained by the U.S. in the war against Spain; later with reference to Jews in European nations; see assimilation + -ist. In Portuguese, assimilado (literally "assimilated," past participle of assimilar) was used as a noun of natives of the Portuguese colonies in Africa who were admitted to equal rights and citizenship.
assimilative (adj.) Look up assimilative at Dictionary.com
1520s; see assimilate + -ive. Alternative assimilatory is from 1775.
assist (n.) Look up assist at Dictionary.com
1570s, "an act of assistance," from assist (v.). In the sporting sense attested 1877 in baseball, 1925 in ice hockey.
assist (v.) Look up assist at Dictionary.com
early 15c., from Old French assister "to stand by, help, put, place, assist" (14c.), from Latin assistere "stand by, take a stand near, attend," from assimilated form of ad "to" (see ad-) + sistere "stand still, take a stand; to set, place, cause to stand," from PIE *si-st-, reduplicated form of root *sta- "to stand, make or be firm." Related: Assisted; assisting. Medical assisted suicide attested from 1884.
assistance (n.) Look up assistance at Dictionary.com
early 15c., "act of helping or aiding; help given, aid," from Old French assistance and Medieval Latin assistentia, from the respective verbs (see assist (v.)).
assistant (n.) Look up assistant at Dictionary.com
mid-15c., assistent "one who helps or aids another," from Latin assistentem (nominative assistens), noun use of present participle of assistere "stand by, attend" (see assist (v.)). The spelling changed in French then (16c.) in English.
assistant (adj.) Look up assistant at Dictionary.com
mid-15c., "helpful, of assistance," from Latin assistentem (nominative assistens), present participle of assistere "stand by, attend" (see assist (v.)). The spelling changed in French then (16c.) in English.
assize (n.) Look up assize at Dictionary.com
"session of a law court," c. 1300 (attested from mid-12c. in Anglo-Latin), from Old French assise "session, sitting of a court" (12c.), noun use of fem. past participle of asseoir "to cause to sit," from Latin assidere/adsidere "to sit beside" (and thus to assist in the office of a judge), "sit with in counsel or office," from ad "to" (see ad-) + sedere "to sit," from PIE root *sed- (1) "to sit." Originally "all legal proceedings of the nature of inquests or recognitions;" hence sessions held periodically in each county of England to administer civil and criminal justice.
associate (n.) Look up associate at Dictionary.com
1530s, "a partner in interest or business," from associate (adj.). Meaning "one admitted to a subordinate degree of membership" is from 1812.
associate (v.) Look up associate at Dictionary.com
mid-15c., "join in company, combine intimately" (transitive), from Latin associatus past participle of associare "join with," from assimilated form of ad "to" (see ad-) + sociare "unite with," from socius "companion, ally," from PIE *sokw-yo-, suffixed form of root *sekw- (1) "to follow." Related: Associated; associating. Intransitive sense of "have intercourse, be associated" is from 1640s. Earlier form of the verb was associen (late 14c.), from Old French associier "associate (with)."
associate (adj.) Look up associate at Dictionary.com
early 15c., "allied, connected, paired; joined in an interest, object, employment or purpose," from Latin associatus, past participle of associare "join with," from assimilated form of ad "to" (see ad-) + sociare "unite with," from socius "companion, ally," from PIE *sokw-yo-, suffixed form of root *sekw- (1) "to follow."
association (n.) Look up association at Dictionary.com
1530s, "action of coming together for a common purpose," from Medieval Latin associationem (nominative associatio), noun of action from past participle stem of associare "join with," from assimilated form of ad "to" (see ad-) + sociare "unite with," from socius "companion, ally" (from PIE *sokw-yo-, suffixed form of root *sekw- (1) "to follow"). Meaning "an organized body of persons with a common purpose" is from 1650s. Meaning "mental connection" is from 1680s; that of "quality or thing called to mind by something else" is from 1810.
associative (adj.) Look up associative at Dictionary.com
"resulting from association," 1804, from associate (v.) + -ive.
assonance (n.) Look up assonance at Dictionary.com
1727, "resemblance of sounds between words other than rhyme," from French assonance, from assonant, from Latin assonantem (nominative assonans), present participle of assonare/adsonare "to resound, respond," from ad "to" (see ad-) + sonare "to sound," from PIE *swene-, from root *swen- "to sound" (see sound (n.1)).

More specific sense in prosody of "rhyming or correspondence of accented vowels but not consonants" is from 1823. In 20c. the sense tended to merge with consonance in the notion of slant rhyme, off rhyme, but properly there is a distinction.
Assonance is the relationship between words with different consonants immediately preceding and following the last accented vowels, which vowels have identical sounds (hit/will, disturb/bird, absolute/unglued). Consonance is the relationship between words whose final accented vowel sounds are different but with the same consonant frame (truck/trick, billion/bullion, impelling/compiling, trance/trounce). [Miller Williams, "Patterns of Poetry"]
assort (v.) Look up assort at Dictionary.com
late 15c., "to distribute into groups or classes," from Old French assorter "to assort, match" (15c., Modern French assortir), from a- "to" (see ad-) + sorte "kind, category," from Latin sortem (nominative sors); see sort (n.). Related: Assorted; assorting.
assorted (adj.) Look up assorted at Dictionary.com
"consisting of selected kinds arranged in sorts," 1797, past participle adjective from assort (v.).
assortment (n.) Look up assortment at Dictionary.com
1610s, "action of arranging into kinds or classes," from assort + -ment. Sense of "group of things of the same sort" is attested from 1759; that of "group of arranged things whether of the same sort or not" from 1791.
assuage (v.) Look up assuage at Dictionary.com
"to soften," usually figuratively, of pain, anger, passion, grief, etc., c. 1300, from Anglo-French assuager, Old French assoagier "soften, moderate, alleviate, calm, soothe, pacify," from Vulgar Latin *adsuaviare, from Latin ad "to" (see ad-) + suavis "sweet, agreeable," from PIE root *swād- "sweet, pleasant" (see sweet (adj.)). For sound development in French, compare deluge from Latin diluvium, abridge from abbreviare. Related: Assuaged; assuaging.
assuasive (adj.) Look up assuasive at Dictionary.com
"mitigating, soothing," 1708, probably from assume on model of persuasive, etc.
assumable (adj.) Look up assumable at Dictionary.com
"capable of being assumed," 1780 (re-assumable is from 1724), from assume + -able. Related: Assumably; assumability.
assume (v.) Look up assume at Dictionary.com
early 15c., "to arrogate, take upon oneself," from Latin assumere, adsumere "to take up, take to oneself, take besides, obtain in addition," from ad "to, toward, up to" (see ad-) + sumere "to take," from sub "under" (see sub-) + emere "to take," from PIE root *em- "to take, distribute" (see exempt (adj.)).

Meaning "to suppose, to take for granted without proof as the basis of argument" is first recorded 1590s; that of "to take or put on fictitiously" (an appearance, etc.) is from c. 1600. Related: Assumed; assuming. Early past participle was assumpt. In rhetorical usage, assume expresses what the assumer postulates, often as a confessed hypothesis; presume expresses what the presumer really believes. Middle English also had assumpten "to receive up into heaven" (especially of the Virgin Mary), from the Latin past participle.
assumpsit (n.) Look up assumpsit at Dictionary.com
"legal action for recovery of damages through breach of contract," legal Latin, literally "he has taken upon himself," perfect indicative of assumere "to take up, take to oneself" (see assume). The word embodies the allegation that the defendant promised or undertook to perform the specified act.
assumption (n.) Look up assumption at Dictionary.com
c. 1300, "the reception, uncorrupted, of the Virgin Mary into Heaven" (also the Aug. 15 Church festival commemorating this, Feast of the Assumption), from Old French assumpcion, asumpsion (13c.) and directly from Latin assumptionem (nominative assumptio) "a taking up, receiving, acceptance, adoption," noun of action from past participle stem of assumere "take up, take to oneself" (see assume).

Meaning "minor premise of a syllogism" is late 14c. Meaning "appropriation of a right or possession" is mid-15c. in English, from a Latin use (Cicero). Meaning "action of taking for oneself" is recorded from 1580s; that of "something taken for granted" is from 1620s.
assumptive (adj.) Look up assumptive at Dictionary.com
early 15c., from Mwdieval Latin assumptivus, from assumpt-, past participle stem of assumere/adsumere "take up, take to oneself" (see assume) + -ive. Oldest sense in English is medical, of bloodletting, "withdrawing humours from opposite parts of the body."
assurance (n.) Look up assurance at Dictionary.com
late 14c., "formal or solemn pledge, promise," also "certainty, full confidence," from Old French asseurance "assurance, promise; truce; certainty, safety, security" (11c., Modern French assurance), from asseurer "to reassure, to render sure" (see assure). Meaning "self-confident" is from 1590s. The word had a negative tinge 18c., often suggesting impudence or presumption.
assure (v.) Look up assure at Dictionary.com
late 14c., "reassure, give confidence to; make secure or safe, protect; bind by a pledge, give a promise or pledge (to do something)," from Old French asseurer "to reassure, calm, protect, to render sure" (12c., Modern French assurer), from Vulgar Latin *assecurar, from assimilated form of Latin ad "to" (see ad-) + securus "safe, secure" (see secure (adj.)). Related: Assured; assuring.
assured (adj.) Look up assured at Dictionary.com
late 14c., of persons, "confident, self-assured," past participle adjective from assure. From early 15c. as "secure, made safe." Related: Assuredly; assuredness.
Assyria Look up Assyria at Dictionary.com
Middle English, from Latin Assyria, from Greek Assyria, short for Assyria ge "the Assyrian land," from fem. of Assyrios "pertaining to Assyria," from Akkadian Ashshur, name of the chief city of the kingdom and also of a god, probably from Assyrian sar "prince." Compare Syria. Related: Assyrian.
Assyriology (n.) Look up Assyriology at Dictionary.com
1846, from Assyria + -ology. Related: Assyriologist.
Astarte Look up Astarte at Dictionary.com
name of a Phoenician goddess identified by the Greeks with their Aphrodite, from Greek Astarte, from Phoenician Astoreth (plural Ashtaroth), equivalent to Assyrian Ishtar. Apparently properly a virginal goddess of the moon or the heavens, but she has been frequently confounded since Biblical times with the sensual Ashera.
astatic (adj.) Look up astatic at Dictionary.com
"unsteady, unstable, taking no fixed position," 1827, with -ic + Greek astatos "unstable, not steadfast," from a- "not, without" (see a- (3)) + statos "placed, standing," from PIE root *sta- "to stand, make or be firm." Related: Astatically.
astatine (n.) Look up astatine at Dictionary.com
radioactive element, named 1947, from Greek astatos "unstable" (see astatic) + chemical suffix -ine (2). So called for its short half-life and lack of stable isotopes. "The element appears not to have a stable form and probably does not exist in nature" [Flood, "Origin of Chemical Names"].
asteism (n.) Look up asteism at Dictionary.com
"genteel irony, polite mockery," 1580s, from Greek asteismos "wit, witticism," from asteios "refined, elegant, witty, clever," literally "of a city or town" (as opposed to "country"), from asty "town, city," especially (without the article) "Athens," which is possibly from a suffixed form of PIE root *wes- (3) "to live, dwell, stay" (see Vesta). For sense, compare urbane.
aster (n.) Look up aster at Dictionary.com
flower genus, 1706, from Latin aster "star," from Greek aster (from PIE root *ster- (2) "star"); so called for the radiate heads of the flowers. Originally used in English in the Latin sense (c. 1600) but this is obsolete.
asterisk (n.) Look up asterisk at Dictionary.com
"figure used in printing and writing to indicate footnote, omission, etc., or to distinguish words or phrases as conjectural," late 14c., asterich, asterisc, from Late Latin asteriscus, from Greek asteriskos "little star," diminutive of aster "star" (from PIE root *ster- (2) "star"). As a verb from 1733.
asterism (n.) Look up asterism at Dictionary.com
1590s, "a constellation, a group of stars," from Greek asterismos "a marking with stars," from aster "star" (from PIE root *ster- (2) "star"). Originally any grouping of stars, whether a constellation or not; in modern use usually the latter. The "Big Dipper" is an asterism; Ursa Major is the constellation which contains it. Other examples are the "Summer Triangle," "the sickle" of Leo, "the teapot" of Sagittarius.
astern (adv.) Look up astern at Dictionary.com
"toward the hinder part of a ship," 1620s, from a- (1) "on" + stern (n.).
asteroid (n.) Look up asteroid at Dictionary.com
"one of the planetoids orbiting the sun, found mostly between Mars and Jupiter," 1802, coined probably by German-born English astronomer William Herschel (1738-1822) from Greek asteroeides "star-like," from aster "star" (from PIE root *ster- (2) "star") + -eidos "form, shape" (see -oid). Related: Asteroidal.
asthenia (n.) Look up asthenia at Dictionary.com
"weakness, debility," 1788, medical Latin, from Greek astheneia "want of strength, weakness, feebleness, sickness; a sickness, a disease," from asthenes "weak, without strength, feeble," from a- "not, without" (see a- (3)) + sthenos "strength, power, ability, might," which is of unknown origin.