Online Etymology Dictionary

applet (n.): by 1995, a diminutive formation from application.
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" (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.): 1818 (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.): "received with gratitude," by 1831; "enhanced in value," 1794; 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 cf. 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.
apprehensible (adj.): late 15c., from Latin apprehensibilis "that can be seized," from apprehens-, past participle stem of apprehendere (see apprehend).
apprehension (n.): "perception, comprehension," late 14c., from Old French apprehension or directly from Latin apprehensionem (nominative apprehensio), noun of action from past participle stem of apprehendere (see apprehend). Sense of "seizure on behalf of authority" is 1570s; that of "anticipation" (usually with dread) is recorded from c.1600.
apprehensive (adj.): late 14c., "capable of perceiving, fitted for mental impression," from Medieval Latin apprehensivus, from Latin apprehensus, past participle of apprehendere (see apprehend). Meaning "fearful of what is to come" is recorded from 1718, via notion of "capable of grasping with the mind" (c.1600). Related: Apprehensively; apprehensiveness.
apprentice (n.): c.1300, from Old French aprentiz "someone learning" (13c., Modern French apprenti, taking the older form as a plural), also as an adjective, "unskilled, inexperienced," from aprendre (Modern French apprendre) "to learn; to teach," contracted from Latin apprehendere (see apprehend). Shortened form prentice long was more usual in English.
apprentice (v.): 1630s, from apprentice (n.). Related: Apprenticed; apprenticing.
apprenticeship (n.): 1590s, from apprentice (n.) + -ship. Replaced earlier apprenticehood (late 14c., with -hood).
apprise (v.): "to notify," 1690s, from French appris, past participle of apprendre "to inform, teach," literally "to lay hold of (in the mind)," another metaphoric meaning of Latin apprehendere (see apprehend). Related: Apprised; apprising.
apprize (v.): occasional legalese form of appraise, c.1400. Related: Apprized; apprizing.
approach (v.): c.1300, from Anglo-French approcher, Old French aprochier "approach, come closer" (12c., Modern French approcher), from Late Latin appropiare "go nearer to," from Latin ad- "to" (see ad-) + Late Latin propiare "come nearer," comparative of Latin prope "near" (see propinquity). Replaced Old English neahlæcan.
approach (n.): mid-15c., from approach (v.). Figurative sense of "means of handling a problem, etc." is first attested 1905.
approachable (adj.): 1570s, from approach (v.) + -able. Figurative sense, "affable, friendly," is from 1610s. Related: Approachably; approachability.
approbate (v.): late 15c., from Latin approbatus, past participle of approbare "to assent to (as good), favor" (see approve). Related: Approbated; approbating.
approbation (n.): late 14c., "proven effectiveness, excellence," from Old French aprobacion or directly from Latin approbationem (nominative approbatio) "an approval," noun of action from past participle stem of approbare (see approve). Meaning "approval, endorsement" is from early 15c.
appropre (v.): mid-14c., from Old French aproprier, from Late Latin appropriare (see appropriate (v.)).
appropriate (v.): early 15c., "take possession of," from Late Latin appropriatus, past participle of appropriare, adpropriare (c.450) "to make one's own," from Latin ad- "to" (see ad-) + propriare "take as one's own," from proprius "one's own" (see proper). Related: Appropriated; appropriating.
appropriate (adj.): "specially suitable, proper," early 15c., from Latin appropriatus, past participle of appropriare (see appropriate (v.)). Related: Appropriately; appropriateness.
appropriation (n.): late 14c., "taking (something) as private property," from Late Latin appropriationem (nominative appropriatio) "a making one's own," noun of action from past participle stem of appropriare (see appropriate). Meaning "setting aside for some purpose" (especially of money) first attested 1789 in U.S. Constitution.
approval (n.): 1680s, from approve + -al (2). According to OED, "Rare bef. 1800; now generally used instead of" approvance (1590s, from French aprovance).
approve (v.): c.1300, "to demonstrate, prove;" mid-14c., "to attest (something) with authority," from Old French aprover (Modern French approuver) "approve, agree to," from Latin approbare "to assent to as good, regard as good," from ad- "to" (see ad-) + probare "to try, test something (to find if it is good)," from probus "honest, genuine" (see prove).

The meaning extended late 14c. to "to sanction, endorse, confirm formally" then to "assent to (something) as good" (early 15c.), especially in reference to the actions of authorities, parliaments, etc. Related: Approved; approving.
approximate (adj.): early 15c., from Latin approximatus, past participle of approximare "to come near to," from ad- "to" (see ad-) + proximare "come near," from proximus "nearest," superlative of prope "near" (see propinquity).
approximate (v.): early 15c., "to bring or put close," from approximate (adj.). Meaning "to come close" is from 1789. Related: Approximated; approximating.