Online Etymology Dictionary

append (v.): late 14c., "to belong to as a possession or right," from Old French apendre (13c.) belong, be dependent (on); attach (oneself) to; hang, hang up," and directly from Latin appendere "to cause to hang (from something), weigh," from ad- "to" (see ad-) + pendere "hang" (see pendant).

Meaning "to hang on, attach as a pendant" is 1640s; that of "attach as an appendix" is recorded by 1843. OED says the original word was obsolete by c. 1500, and these later transitive senses represent a reborrowing from Latin or French. Related: Appended; appending.
appendage (n.): 1640s, from append + -age.
appendectomy (n.): 1891, a hybrid from appendix + -ectomy.
appendices (n.): proper Latin plural of appendix.
appendicitis (n.): 1886, from Latin stem of appendix, in the medical sense, + -itis "inflammation."
appendicular (adj.): 1650s, from Latin appendicula, diminutive of appendix + -ar.
appendix (n.): 1540s, "subjoined addition to a document or book," from Latin appendix "an addition, continuation, something attached," from appendere (see append). Used for "small outgrowth of an internal organ" from 1610s, especially in reference to the vermiform appendix. This sense perhaps from or influenced by French appendix, where the term was in use from 1540s.
apperceive (v.): c. 1300, from Old French apercevoir (see apperception). In modern psychological use, a back-formation from apperception. Related: Apperceived; apperceiving.
apperception (n.): 1753, from French aperception (17c.), from German Apperzeption (or Latin apperceptionem), coined by German mathematician and philosopher Gottfried Wilhelm Leibniz (1646-1716) as noun corresponding to French apercevoir "perceive, notice, become aware of" (11c., from Latin ad "to" (see ad-) + percipere; see perceive) on analogy of Perzeption/percevoir.
appertain (v.): late 14c., from Anglo-French apartenir, Old French apartenir (12c.) "be related to; be incumbent upon," from Late Latin appertinere "to pertain to," from ad- "to, completely" (see ad-) + pertinere "to belong to" (see pertain). To belong as parts to the whole, or as members to a family or class. Related: Appertained; appertaining.
appetence (n.): "strong desire," c. 1600, from French appétence "desire," from Latin appetentia "longing after something," noun of state from appetentem (nominative appetens), present participle of appetere, from ad "to" (see ad-) + petere "to seek, request" (see petition (n.)).
appetite (n.): c. 1300, "craving for food," from Anglo-French appetit, Old French apetit (13c.) "appetite, desire, eagerness," from Latin appetitus "appetite," literally "desire toward," from appetitus, past participle of appetere "to long for, desire; strive for, grasp at," from ad- "to" (see ad-) + petere "go to, seek out" (see petition (n.)).

Of other desires or cravings, from late 14c. As an adjective form, OED lists appetitious (1650s) and appetitual (1610s) as "obsolete," but appetitive (1570s) continues.
appetize (v.): "make hungry," 1782 (implied in appetized), irregularly formed (on model of verbs in -ize) from appetite, or else a back-formation from appetizing.
appetizer (n.): "something taken to whet the appetite," 1820, agent noun from appetize.
appetizing (adj.): "exciting desire or hunger," 1650s, from appetite on model of present participle adjective forms in -ing.
Appian Way: road between Rome and Capua, so called because it was begun (302 B.C.E.) by the consul Appius Claudius Caecus.
applaud (v.): late 15c. (implied in applauding), "to express agreement or approval; to praise," from Latin applaudere "to clap the hands in approbation, to approve by clapping hands; to strike upon, beat," from ad "to" (see ad-) + plaudere "to clap" (see plaudit). Sense of "express approval of" is from 1590s; that of "to clap the hands" is from 1590s. Figurative sense arrived in English before literal. Related: Applauded; applauding.
applause (n.): early 15c., from Latin applausus, past participle of applaudere "approve by clapping hands" (see applaud).
apple (n.): Old English æppel "apple; any kind of fruit; fruit in general," from Proto-Germanic *ap(a)laz (source also of Old Saxon, Old Frisian, Dutch appel, Old Norse eple, Old High German apful, German Apfel), from PIE *ab(e)l "apple" (source also of Gaulish avallo "fruit;" Old Irish ubull, Lithuanian obuolys, Old Church Slavonic jabloko "apple"), but the exact relation and original sense of these is uncertain (compare melon).
A roted eppel amang þe holen, makeþ rotie þe yzounde. ["Ayenbite of Inwit," 1340]
In Middle English and as late as 17c., it was a generic term for all fruit other than berries but including nuts (such as Old English fingeræppla "dates," literally "finger-apples;" Middle English appel of paradis "banana," c. 1400). Hence its grafting onto the unnamed "fruit of the forbidden tree" in Genesis. Cucumbers, in one Old English work, are eorþæppla, literally "earth-apples" (compare French pomme de terre "potato," literally "earth-apple;" see also melon). French pomme is from Latin pomum "apple; fruit" (see Pomona).
As far as the forbidden fruit is concerned, again, the Quran does not mention it explicitly, but according to traditional commentaries it was not an apple, as believed by Christians and Jews, but wheat. ["The Heart of Islam: Enduring Values for Humanity," Seyyed Hossein Nasr, 2002]
Apple of Discord (c. 1400) was thrown into the wedding of Thetis and Peleus by Eris (goddess of chaos and discord), who had not been invited, and inscribed kallisti "To the Prettiest One." Paris, elected to choose which goddess should have it, gave it to Aphrodite, offending Hera and Athene, with consequences of the Trojan War, etc.

Apple of one's eye (Old English), symbol of what is most cherished, was the pupil, supposed to be a globular solid body. Apple-polisher "one who curries favor" first attested 1928 in student slang. The image of something that upsets the apple cart is attested from 1788. Road apple "horse dropping" is from 1942.
apple pie: attested from 1580s, from apple + pie; noted by 1893 as a typical American dish. Apple-pie bed as a name for a childish prank is recorded from 1781; supposedly from the way of making apple turnovers, but some think it a folk etymology of French nappe pliée "folded sheet."
applesauce (n.): by 1739, American English, from apple + sauce. Slang meaning "nonsense" is attested from 1921 and was noted as a vogue word early 1920s. Mencken credits it to cartoonist T.A. ("Tad") Dorgan. DAS suggests the word was thus used because applesauce was cheap fare served in boardinghouses.
applet (n.): by 1995, a diminutive formation from application + -let.
appliance (n.): 1560s, "action of putting into use," from apply + -ance. Meaning "instrument, thing applied for a purpose" is from 1590s.
applicability (n.): 1650s, from applicable + -ity.
applicable (adj.): 1560s, "pliable," with -able + Latin applicare (see apply). Meaning "capable of being applied" is from 1650s; earlier in this sense was appliable (mid-15c.).
applicant (n.): "one who applies," late 15c., from Latin applicantem (nominative applicans), present participle of applicare (see apply).
application (n.): early 15c., "the bringing of something to bear on something else," from Old French aplicacion (14c.), from Latin applicationem (nominative applicatio) "a joining to, an attaching oneself to," noun of action from past participle stem of applicare (see apply). Meaning "sincere hard effort" is from c. 1600. Meaning "a formal request to be hired for a job or paid position" is by 1851.
applied (adj.): "put to practical use," (as opposed to abstract or theoretical), 1650s, from past participle of apply. Earlier it was used in a sense of "folded" (c. 1500).
applique (n.): 1841, from French appliqué "work applied or laid on another material," noun use of past participle of appliquer "to apply" (12c.), from Latin applicare (see apply).
apply (v.): late 14c., "to put (one's faculties, etc.) to some task or career," late 14c., from Old French aploiier "apply, use, attach" (12c., Modern French appliquer), from Latin applicare "attach to, join, connect;" figuratively, "devote (oneself) to, give attention," from ad- "to" (see ad-) + plicare "fold" (see ply (v.1)). The etymological sense is "bring things in contact with one another." Of lotions, from early 15c. Meaning "seek a job by submitting an application for one" is from 1851. A by-form applicate is recorded from 1530s. Related: Applied; applying.
appoint (v.): late 14c., "to decide, resolve; to arrange the time of (a meeting, etc.)," from Anglo-French appointer, Old French apointier "make ready, arrange, settle, place" (12c.), from apointer "duly, fitly," from phrase à point "to the point," from a- "to" (see ad-) + point "point," from Latin punctum (see point (n.)). The ground sense is "to come to a point (about some matter)," therefore "agree, settle." Meaning "put (someone) in charge" is early 15c. Related: Appointed; appointing.
appointed (adj.): with qualifying adverb, "equipped, furnished," 1530s, from past participle of appoint (v.).
appointee (n.): 1768, after French appointé, from apointer (see appoint + -ee).
appointment (n.): early 15c., "an agreement," also "a fixing of a date for official business," from Middle French apointement, from apointer (see appoint). Meaning "act of placing in office" is attested from 1650s.
Appomattox: eccentric spelling of plural of Appomattoc, name of a local subgroup of the Powhatan (Algonquian) confederacy in Virginia (first attested as Apamatic, 1607). Site of last battle for Army of Northern Virginia (CSA) in the American Civil War, and of Lee's surrender to Grant in Wilmer McLean house, April 9, 1865.
apportion (v.): 1570s, from Middle French apportionner, from Old French aporcioner "apportion, share out," from a- "to" (see ad-) + portioner "to divide into portions," from portion "share, portion" (see portion). Related: Apportioned; apportioning.
apportionment (n.): 1620s, from apportion + -ment. Perhaps influenced by French apportionnement.
appose (v.): "to apply" (one thing to another), 1590s, either from French apposer (from a "to;" see ad-, + poser "to place;" see pose (v.1)), or else formed in English from Latin apponere (see apposite) on analogy of compose, expose, etc. In Middle English, an identical word was a variant spelling of oppose. Related: Apposed; apposing.
apposite (adj.): 1620s, "well-put or applied, appropriate," from Latin appositus "contiguous, neighboring;" figuratively "fit, proper, suitable," past participle of apponere "apply to, put near," from ad- "near" (see ad-) + ponere "to place" (past participle positus; see position (n.)).
apposition (n.): "application" (of one thing to another), mid-15c., originally in grammatical sense, from Latin appositionem (nominative appositio), noun of action from past participle stem of apponere "to put to" (see apposite). General sense is from 1540s.
appositive (adj.): 1690s, from Latin appositus, past participle of apponere "to put to" (see apposite) + -ive. As a noun, from 1847.
appraisal (n.): "setting of a price," by 1784, American English, from appraise + -al (2). Figurative sense, "act of appraising" (originally a term of literary criticism) is from 1817.
appraise (v.): c. 1400, "to set a value on," from stem of Old French aprisier "apraise, set a price on" (14c., Modern French apprécier), from Late Latin appretiare "value, estimate," from ad- "to" (see ad-) + pretium "price" (see price (n.)). Original English spelling apprize altered by influence of praise. Related: Appraised; appraising.
appraiser (n.): early 15c., agent noun from appraise (v.).
appreciable (adj.): 1779 (mid-15c. in sense "worthy"); from French appréciable and directly from Medieval Latin appretiabilis, from Late Latin appretiare (see appreciate). Related: Appreciably.
appreciate (v.): 1650s, "to esteem or value highly," from Late Latin appretiatus, past participle of appretiare "to set a price to" (see appraise). Meaning "to rise in value" (intransitive) first recorded 1789. Related: Appreciated; appreciating.
appreciated (adj.): "enhanced in value," 1794; "received with gratitude," by 1831; past participle adjective from appreciate.
appreciation (n.): c. 1600 (with an isolated use from c. 1400), from Anglo-French appreciation, noun of action from Old French apprécier (14c.), from Late Latin appretiare "estimate the quality of" (see appreciate). Generally with a sense of "high estimation" from c. 1650. Meaning "expression of (favorable) estimation" is from 1858; sense of "rise in value" is from c. 1790.
appreciative (adj.): 1650s (implied in appreciatively); see appreciate + -ive. Related: Appreciativeness.
apprehend (v.): mid-14c., "to grasp in the senses or mind," from Old French aprendre (12c.) "teach; learn; take, grasp; acquire," or directly from Latin apprehendere "to take hold of, grasp," from ad- "to" + prehendere "to seize" (see prehensile). Metaphoric extension to "seize with the mind" took place in Latin, and was the sole sense of cognate Old French aprendre (Modern French apprendre "to learn, to be informed about;" also compare apprentice). Original sense returned in English in meaning "to seize in the name of the law, arrest," recorded from 1540s, which use probably was taken directly from Latin. Related: Apprehended; apprehending.