additive (adj.) Look up additive at Dictionary.com
1690s, "tending to be added," from Late Latin additivus "added, annexed," from past participle stem of Latin addere "add to, join, attach" (see addition). Alternative addititious "additive, additional" (1748) is from Latin additicius "additional."
addle (v.) Look up addle at Dictionary.com
"become putrid," hence "be spoiled, be made worthless or ineffective," 1640s (implied in addled), from archaic addle (n.) "urine, liquid filth," from Old English adela "mud, mire, liquid manure" (cognate with East Frisian adel "dung," Old Swedish adel "urine," Middle Low German adel "mud," Dutch aal "puddle").

Popularly used in the noun phrase addle egg (mid-13c.) "egg that does not hatch, rotten egg," a loan-translation of Latin ovum urinum, literally "urine egg," which is itself an erroneous loan-translation of Greek ourion oon "putrid egg," literally "wind egg," from ourios "of the wind" (confused by Roman writers with ourios "of urine," from ouron "urine").

From this phrase, since c. 1600 the noun in English was mistaken as an adjective meaning "putrid," and thence given a figurative extension to "empty, vain, idle," also "confused, muddled, unsound" (1706), then back-formed into a verb in that sense. Related: Addling. Popular in forming derogatory compounds 17c. and after, such as addle-headed "stupid, muddled" (1660s); addle-pated (1630s); addle-pate "stupid bungler" (c. 1600).
address (v.) Look up address at Dictionary.com
early 14c., "to guide, aim, or direct," from Old French adrecier "go straight toward; straighten, set right; point, direct" (13c.), from Vulgar Latin *addirectiare "make straight" (source also of Spanish aderezar, Italian addirizzare), from ad "to" (see ad-) + *directiare "make straight," from Latin directus "straight, direct" (see direct (v.), and compare dress (v.)).

Oldest sense in English is preserved in golf (to address a ball). Meaning "direct for transmission, write as a destination on a message" is from mid-15c. Meaning "to direct spoken words (to someone)" is from late 15c. Late 14c. as "to set in order, repair, correct." The attempt (falsely) re-Latinize the spelling to add- began in France 15c. but failed there (the Modern French verb is adresser), however it stuck in English. Related: Addressed; addressing.
address (n.) Look up address at Dictionary.com
1530s, "dutiful or courteous approach," from address (v.) and from French adresse (13c., from the verb in French). Meaning "power of directing one's actions and conduct" is from 1590s. Meaning "act or manner of speaking to" is from 1670s. Sense of "formal speech to an audience" (Gettysburg Address, etc.) is from 1751. Sense of "superscription of a letter" (guiding it to its destination) is from 1712 and led to the meaning "place of residence" (by 1888). Transferred use in computer programming is from 1948. Middle English had a noun addressing "control, correction" (late 14c.).
addressee (n.) Look up addressee at Dictionary.com
"one to whom anything is addressed," 1810; see address (v.) + -ee.
adduce (v.) Look up adduce at Dictionary.com
early 15c., from Latin adducere "lead to, bring to, bring along," from ad- "to" (see ad-) + ducere "to lead," from PIE root *deuk- "to lead" (see duke (n.)). Related: Adduced; adducing.
To allege is to make an unsupported statement regarding something; to adduce, on the other hand, is to bring forward proofs or evidence in support of some statement or proposition already made: as, he alleged that he had been robbed by A. B., but adduced no proof in support of his allegation. [Century Dictionary]
adduction (n.) Look up adduction at Dictionary.com
"the act of drawing toward a common center or median line," 1650s, from French adduction (16c.), from Medieval Latin adductionem (nominative adductio), noun of action from past participle stem of adducere "lead to, bring to" (see adduce). Related: Adduct; adductor; adductive.
Adelaide Look up Adelaide at Dictionary.com
fem. proper name, from French Adélaide, from a Germanic source similar to Old High German Adalhaid, from adal "noble family" (see atheling) + German heit "state, rank," which is related to Old English -had "person, degree, state, nature" (see -hood). The first element affixed to French fem. ending -ine gave Adeline.
Adeline Look up Adeline at Dictionary.com
fem. proper name, from French, of Germanic origin, literally "noblewoman," from adal "noble family" (see atheling) + French fem. suffix -ine (see -ine (1)).
Adelphi Look up Adelphi at Dictionary.com
district of London, so called because it was laid out c. 1768 and built by four brothers of a family named Adam; from Greek adelphos "brother," literally "from the same womb, co-uterine," from copulative prefix a- "together with" + delphys "womb," which is perhaps related to dolphin. The district was the site of the popular Adelphi theater c. 1882-1900, which gave its name to a style of performance.
Aden Look up Aden at Dictionary.com
place in southern Arabia, ultimately from Akkadian edinnu "plain," which some think also is the root of Biblical Eden. The two place-names sometimes were treated as synonymous in English (Byron, Poe, etc.).
adenine (n.) Look up adenine at Dictionary.com
crystaline base, 1885, coined by German physiologist/chemist Albrecht Kossel (1853-1927) from Greek aden "gland," from PIE root *engw- "internal organ" (see inguinal) + chemical suffix -ine (2). So called because it was derived from the pancreas of an ox.
adeno- Look up adeno- at Dictionary.com
scientific word-forming element meaning "gland," from Greek aden "gland," from a suffixed form of PIE root *engw- "groin; internal organ" (source also of Latin inguen "groin;" see inguinal).
adenoid (adj.) Look up adenoid at Dictionary.com
1839, "gland-like," from medical Latin adenoideus, from Greek adenoeides, from aden (genitive adenos) "gland" (from PIE root *engw- "internal organ;" see inguinal) + eidos "form" (see -oid). Adenoids "adenoid growths" is attested by 1856.
adenoidal (adj.) Look up adenoidal at Dictionary.com
1852, "gland-like, resembling a gland," from adenoid + -al (1). From 1919 as "having the appearance of one with adenoids."
adept (n.) Look up adept at Dictionary.com
"an expert, one who as attained knowledge," especially "one who is skilled in the secrets of an occult science," 1660s, from Latin adeptus (adj.) "having attained" (see adept (adj.)). The Latin adjective was used as a noun in this sense in Medieval Latin among alchemists. It implies natural and acquired ability, whereas expert implies more of experience and practice.
adept (adj.) Look up adept at Dictionary.com
1690s, "completely skilled, well-versed," from Latin adeptus "having reached or attained," past participle of adipisci "to come up with, arrive at," figuratively "to attain to, acquire," from ad- "to" (see ad-) + apisci "to grasp, attain" (related to aptus "fitted," from PIE root *ap- (1) "to take, reach" (see apt). Related: Adeptly; adeptness.
adequacy (n.) Look up adequacy at Dictionary.com
1794; see adequate + -cy. Adequateness is from 1670s.
adequate (adj.) Look up adequate at Dictionary.com
1610s, "equal to what is needed or desired, sufficient," from Latin adaequatus "equalized," past participle of adaequare "to make equal to, to level with," from ad- "to" (see ad-) + aequare "make level," from aequus "equal, even" (see equal (adj.)). The sense is of being "equal to what is required." It shares duty with enough, depending on the subject. With a slightly disparaging tinge, "mediocre, just good enough," by 1900. Related: Adequateness.
adequately (adv.) Look up adequately at Dictionary.com
1620s; see adequate + -ly (2); originally a term in logic in reference to correspondence of ideas and objects and probably based on Latin use. Meaning "suitably" is recorded from 1680s.
adhere (v.) Look up adhere at Dictionary.com
1590s, from Middle French adhérer "to stick, adhere" (15c., corrected from earlier aderer, 14c.) or directly from Latin adhaerare "to stick, cling to," from ad- "to" (see ad-) + haerere "to stick" (see hesitation). Originally often of persons, "to cleave to a leader, cause, party, etc." (compare adherent (n.), which still often retains this sense). Related: Adhered; adhering.
adherence (n.) Look up adherence at Dictionary.com
mid-15c., "steady attachment of the mind or feelings to a person, cause, belief, etc.," from Middle French adhérence, from Medieval Latin adhaerentia, abstract noun from Latin adhaerent-, stem of adhaerens, present participle of adhaerare "stick to," from ad- "to" (see ad-) + haerere "to stick" (see hesitation). Rarely in a physical sense, adhesion being the usual word for that.
adherent (n.) Look up adherent at Dictionary.com
early 15c., "follower, supporter, one who upholds (a leader, cause, etc.)," from Old French adherent or directly from Latin adhaerentem (nominative adhaerens), present participle of adhaerere "stick to," from ad- "to" (see ad-) + haerere "to stick" (see hesitation). Meaning "adhesive substance" is from 1912.
adherent (adj.) Look up adherent at Dictionary.com
late 14c., "sticking, clinging to, adhesive," from Old French adherent or directly from Latin adhaerentem (nominative adhaerens), present participle of adhaerere "stick to," from ad- "to" (see ad-) + haerere "to stick" (past participle haesus; see hesitation).
adhesion (n.) Look up adhesion at Dictionary.com
1620s, "act or state of sticking or being stuck, a being united or attached," from French adhésion or directly from Latin adhaesionem (nominative adhaesio) "a sticking to," noun of action from past participle stem of adhaerare "to stick to, cling to," from ad- "to" (see ad-) + haerere "to stick" (see hesitation). The earliest English use is of persons ("faith is adhesion unto God"), but "Adhesion is generally used in the material, and adherence in the metaphysical sense." [Johnson]
adhesive (adj.) Look up adhesive at Dictionary.com
1660s, from French adhésif, formed in French from Latin adhaes-, past participle stem of adhaere (see adherent (adj.)).
adhesive (n.) Look up adhesive at Dictionary.com
1881, from adhesive (adj.). Originally of postage stamps, short for adhesive stamp (1840). By 1900 as "a substance that causes to adhere."
adiabatic (adj.) Look up adiabatic at Dictionary.com
"without transference, impossible (to heat)," 1838, with -ic + Greek adiabatos "not to be passed" (of rivers, etc.), from a- "not" (see a- (3)) + diabatos "to be crossed or passed, fordable," from dia "through" (see dia-) + batos "passable," from bainein "to go, walk, step," from PIE root *gwā- "to go, to come" (see come). In thermodynamics, of a change in volume without change in heat.
adiaphorous (adj.) Look up adiaphorous at Dictionary.com
"indifferent, non-essential, morally neither right nor wrong," 1630s, from Greek adiaphoros "not different; indifferent," from a- "not" (see a- (3)) + diaphoros "different."
adieu (interj.) Look up adieu at Dictionary.com
late 14c., adewe, from Old French a Dieu, a Deu, shortened from phrases such as a dieu (vous) commant "I commend (you) to God," from a "to" (see ad) + dieu "God," from Latin deum, accusative of deus "god," from PIE *deiwos "god" (see Zeus). Originally said to the party left (farewell was to the party setting forth), but in English used as a general parting salutation. As a noun, "expression of kind wishes upon departure," late 14c. Compare native parting salutation good-bye, a contraction of God be with ye.
adios (interj.) Look up adios at Dictionary.com
1837, American English, from Spanish adios, from phrase a dios vos acomiendo "I commend you to God;" the French form is adieu.
adipose (adj.) Look up adipose at Dictionary.com
"pertaining to fat, fatty," 1743, from Modern Latin adiposus "fatty," from Latin adipem (nominative adeps, genitive adipis) "soft fat of animals, fat, lard," which is said to be from Greek aleipha "unguent, fat, anything used for smearing," a word related to lipos "grease, fat," from PIE root *leip- "to stick, adhere," also used to form words for "fat" (see leave (v.)). With change of -l- to -d- "prob. due to Umbrian influence" [Klein]. But it could as well be a native Italic formation from the same roots, *ad-leip-a "sticking onto."
Adirondack (adj.) Look up Adirondack at Dictionary.com
1906 in reference to a type of lawn or deck chair said to have been designed in 1903 by a Thomas Lee, owner of the Westport Mountain Spring, a resort in the Adirondack region of New York State, and commercially manufactured the following year, but said originally to have been called Westport chair after the town where it was first made.

Adirondack Mountains is a back-formation from Adirondacks, which was treated as a plural noun but really it is from Mohawk (Iroquoian) adiro:daks "tree-eaters," a name they applied to neighboring Algonquian tribes. The -s is an imperfective affix.
adit (n.) Look up adit at Dictionary.com
"entrance," especially "horizontal mine excavation," c. 1600, from Latin aditus "an approach, an entrance; a going to or drawing near," from past participle stem of adire "to approach," from ad- "to" (see ad-) + ire (past participle itus) "to go," from PIE root *ei- (1) "to go" (see ion).
adjacence (n.) Look up adjacence at Dictionary.com
c. 1600, from Medieval Latin adjacentia, abstract noun from Latin adiacens "lying at," present participle of adiacere "lie at, border upon, lie near," from ad- "to" (see ad-) + iacere "to lie, rest," literally "to throw" (see jet (v.)).
adjacent (adj.) Look up adjacent at Dictionary.com
early 15c., "contiguous, bordering; close, nearby," from Latin adiacentem (nominative adiacens) "lying at," present participle of adiacere "lie at, border upon, lie near," from ad- "to" (see ad-) + iacēre "to lie, rest," related to iacere "to throw; lay ('cast (oneself) down')," from PIE root *ye- "to throw, impel" (see jet (v.)), with notion of "to cast (oneself) down." Only of things, never of persons or animals. Adjacent, properly, is near but not necessarily in contact; adjoining is so as to touch. Latin adiacentia meant "the neighborhood."
adjectival (adj.) Look up adjectival at Dictionary.com
1797, from adjective + -al (1). Related: Adjectivally.
adjective (n.) Look up adjective at Dictionary.com
"word used to qualify, limit, or define a noun or noun-like part of speech," late 14c., short for noun adjective, from Old French adjectif (14c.), from Latin adjectivum "that is added to (the noun)," neuter of adjectivus "added," past participle of adicere "throw to, fling at, throw or place (a thing) near," especially "add in addition, add by way of increase," from ad- "to" (see ad-) + comb. form of iacere "to throw" (see jet (v.)). In Britain from at least 1851 the word often was a euphemism for the taboo adjective bloody.
They ... slept until it was cool enough to go out with their 'Towny,' whose vocabulary contained less than six hundred words, and the Adjective. [Kipling, "Soldiers Three," 1888]
adjoin (v.) Look up adjoin at Dictionary.com
c. 1300, "unite (something to something else), ally" (a sense now obsolete); late 14c. as "be contiguous with, be adjacent to," from Old French ajoin- stem of ajoindre "join together, unite," from Latin adiungere "fasten on, harness, join to," from ad- "to" (see ad-) + iungere "to bind together," from a nasalized form of PIE root *yeug- "to join" (see jugular). Meaning "be contiguous with, be in contact with" is from late 14c. Thje French word was Latinized 16c. to Modern French adjoindre. Related: Adjoined; adjoining.
adjourn (v.) Look up adjourn at Dictionary.com
mid-14c., ajournen, "assign a day, fix a day" (for convening or reconvening of an organized body), from Old French ajorner (12c.) "meet" (at an appointed time), from the phrase à jorn "to another day, to a (stated) day," from à "to" (see ad-) + journ "day," from Latin diurnus "daily" (see diurnal).

The notion is of setting a date for re-meeting. Meaning "to close a meeting" (with or without intention to reconvene) is from early 15c. Meaning "to go in a body to another place" (1640s) is colloquial. The English word has had the -d- since 16c., but the spelling is unetymological, as the compound apparently is not from Latin; Middle French also occasionally has adjourner, but this was rejected in Modern French. Related: Adjourned; adjourning.
adjournment (n.) Look up adjournment at Dictionary.com
mid-15c., from Old French ajornement "daybreak, dawn; summons (to appear in court)," from ajorner (see adjourn), with unetymological -d- added in English on the mistaken notion of a Latin origin.
Adjournment is the act by which an assembly suspends its session in virtue of authority inherent in itself; it may be also the time or interval of such suspension. A recess is a customary suspension of business, as during the period of certain recognized or legal holidays .... Recess is also popularly used for a brief suspension of business for any reason: as, it was agreed that there be a recess of ten minutes. [Century Dictionary]
adjudge (v.) Look up adjudge at Dictionary.com
late 14c., ajuge, "to make a judicial decision, decide by judicial opinion," from Old French ajugier "to judge, pass judgment on" (Modern French adjuger, the -d- was restored 14c. and English followed suit by 16c.), from Latin adiudicare "grant or award as a judge," from ad- "to" (see ad-) + iudicare "to judge," which is related to iudicem (see judge (v.)). Sense of "have an opinion" is from c. 1400. Related: Adjudged; adjudging.
adjudicate (v.) Look up adjudicate at Dictionary.com
1700, a back-formation from adjudication, or else from Latin adiudicatus, past participle of adiudicare "grant or award as a judge" (see adjudge). Related: Adjudicated; adjudicating.
adjudication (n.) Look up adjudication at Dictionary.com
1690s, "action of adjudging," from French adjudication or directly from Late Latin adiudicationem (nominative adiudicatio), noun of action from past participle stem of adiudicare "grant or award as a judge" (see adjudge). From 1782 as "a judicial settlement."
adjudicative (adj.) Look up adjudicative at Dictionary.com
1809; see adjudicate + -ive. Perhaps modeled on French adjudicatif.
adjudicator (n.) Look up adjudicator at Dictionary.com
1804, agent noun in Latin form from adjudicate.
adjunct (adj.) Look up adjunct at Dictionary.com
"united with another in office or action," 1590s, from Latin adiunctus "closely connected, joined, united," past participle of adiungere "to join to," usually with a notion of subordination, but this is not etymological (see adjoin). Adjunct professor is attested by 1826, American English.
adjunct (n.) Look up adjunct at Dictionary.com
1580s, "something added to but not an essential part of (something else)," from Latin adiunctus "closely connected, joined, united" (as a noun, "a characteristic, essential attribute"), past participle of adiungere "join to" (see adjoin).
adjuration (n.) Look up adjuration at Dictionary.com
late 14c., "exorcism," from Late Latin adiurationem (nominative adiuratio) "a swearing to," noun of action from past participle stem of Latin adiurare "to put (someone) to an oath," from ad- "to" (see ad-) + iurare "swear," from ius (genitive iuris) "law," from PIE root *yewes- "law" (see jurist). Originally a term in exorcism (with conjuration); the general sense "a solemn oath, a charging under the penalty of a curse" is from 17c.
adjure (v.) Look up adjure at Dictionary.com
late 14c., "to bind by oath; to question under oath;" c. 1400 as "to charge with an oath or under penalty of a curse," from Latin adiurare "confirm by oath, add an oath, to swear to in addition; call to witness," in Late Latin "to put (someone) to an oath," from ad- "to" (see ad-) + iurare "swear," from ius (genitive iuris) "law" (see jurist). Related: Adjured; adjuring.