Online Etymology Dictionary

Appalachia: "cultural and geographical region of inland Eastern U.S.," 1880s, from the Appalachian Mountains, which are its core. Earlier Appalachia was proposed as a better name for "United States of America" by Washington Irving in 1839 (though he preferred Alleghenia) and this may have been the coinage of the word.
It is a thousand pities that the puny witticisms of a few professional objectors should have the power to prevent, even for a year, the adoption of a name for our country. At present we have, clearly, none. There should be no hesitation about "Appalachia." In the first place, it is distinctive. "America" is not, and can never be made so. We may legislate as much as we please, and assume for our country whatever name we think right — but to use it will be no name, to any purpose for which a name is needed, unless we can take it away from the regions which employ it at present. South America is "America," and will insist upon remaining so. [Edgar Allan Poe, 1846]
Appalachian: in reference to the North American mountain range, c.1600, Mountaynes Apalatsi; written apalachen by Spanish explorers and originally in reference only to the southern end of the range. Originally the name of the Apalachee, a Muskogean people of northwestern Florida, perhaps from Apalachee abalahci "other side of the river" or Hitchiti (Muskogean) apalwahči "dwelling on one side." Spelling shifted under influence of adjectives in -ian.
appall (v.): also appal, early 14c., "to fade;" c.1400, "to grow pale," from Old French apalir "become or make pale," from a- "to" (see ad-) + palir "grow pale," from Latin pallere (see pallor). Meaning "cause dismay or shock," is 1530s. Related: Appalled; appalling.
appalled (adj.): 1570s, "enfeebled;" c.1600, "dismayed;" past participle adjective from appall.
appalling (adj.): 1620s, present participle adjective from appall. Colloquial weakened sense of "distasteful" is attested from 1919.
Appaloosa: breed of horses favored by Indian tribes in U.S. West, 1849, either from Opelousa in Louisiana or from Palouse Indians, who lived near the river of that name in Idaho, in which case it probably is a Nez Percé word. Opelousa is perhaps from Choctaw api losa "black body;" while Palouse is from Sahaptin palou:s "what is standing up in the water."
appanage (n.): c.1600, from French apanage (13c.), from apaner "to endow with means of subsistence," from Medieval Latin appanare "equip with bread," from ad- "to" (see ad-) + panis "bread" (see food). Originally, provisions made for younger children of royalty. The double -p- restored in French 15c.-16c., in English 17c.
apparat (n.): "administrative machinery of the Communist Party in Russia," 1950, from Russian, from German apparat "apparatus, instrument," from Latin apparatus (see apparatus).
apparatchik (n.): "Communist agent or spy," 1941, originally in writings of Arthur Koestler, from Russian, from apparat "political organization" (see apparat). Russian plural is apparatchiki.
apparatus (n.): 1620s, from Latin apparatus "tools, implements, equipment; preparation, a preparing," noun of state from past participle stem of apparare "prepare," from ad- "to" (see ad-) + parare "make ready" (see pare).
apparel (v.): mid-13c., "to equip (in any way)," from Old French apareillier (12c.), from Vulgar Latin *appariculare. This is either from Latin apparare "prepare, make ready" (see apparatus), or from Vulgar Latin *ad-particulare "to put things together." The meaning "to attire in proper clothing" is from mid-14c. Cognate with Italian aparecchiare, Spanish aparejar, Portuguese aparelhar. Related: Appareled; apparelled; appareling; apparelling.
apparel (n.): "personal outfit or attire," early 14c., also "ship's rigging," from Old French apareil "preparation," from apareillier (see apparel (v.)). Earlier in same sense was apparelment (early 14c.).
apparent (adj.): late 14c., from Old French aparant "evident, obvious, visible," from Latin apparentem (nominative apparens) "visible, manifest," present participle of apparere (see appear). First attested in phrase heir apparent (see heir). Meaning "superficial" is c.1400. Apparent magnitude in astronomy (how bright a heavenly body looks from earth, as opposed to absolute magnitude, which is how bright it really is) is attested from 1875.
apparently (adv.): late 14c., "visibly, openly," from apparent + -ly (2). Meaning "evidently" is from 1550s; that of "to all appearances" (but not necessarily "really") is from 1560s; meaning "so far as can be judged, seemingly," is from 1846. A gradual retreat from certainty.
apparition (n.): c.1500, "unclosing" (of Heaven), from Anglo-French aparicion, Old French apparition, aparoison (15c.), used in reference to the Epiphany (revealing of Christ child to the Wise Men), from Late Latin apparitionem (nominative apparitio) "an appearance," also "attendants," in classical Latin "service, servants," noun of action from past participle stem of apparere "appear" (see appear). Meaning "ghost" first recorded c.1600; the shade of sense differentiation between appearance and apparition is that the latter tends to be unexpected or startling.
appeal (v.): early 14c., originally in legal sense of "to call" to a higher judge or court, from Anglo-French apeler "to call upon, accuse," Old French apeler "make an appeal" (11c., Modern French appeler), from Latin appellare "to accost, address, appeal to, summon, name," iterative of appellere "to prepare," from ad- "to" (see ad-) + pellere "to beat, drive" (see pulse (n.1)). Related: Appealed; appealing.

Probably a Roman metaphoric extension of a nautical term for "driving a ship toward a particular landing." Popular modern meaning "to be attractive or pleasing" is quite recent, attested from 1907 (appealing in this sense is from 1891), from the notion of "to address oneself in expectation of a sympathetic response."
appeal (n.): c.1300, in the legal sense, from Old French apel (Modern French appel), back-formation from apeler (see appeal (v.)). Meaning "call to an authority" is from 1620s; that of "attractive power" attested by 1916.
appealing: mid-15c. as a noun, "action of petitioning a higher court or authority," verbal noun from appeal (v.). Adjectival sense of "attractive" attested by 1892. Related: Appealingly.
appear (v.): late 13c., "to come into view," from stem of Old French aparoir (12c., Modern French apparoir) "appear, come to light, come forth," from Latin apparere "to appear, come in sight, make an appearance," from ad- "to" (see ad-) + parere "to come forth, be visible," from PIE root *per- "to bring forth" (see pare). Of persons, "present oneself," late 14c. Meaning "seem, have a certain appearance" is late 14c. Related: Appeared; appearing.
appearance (n.): late 14c., "visible state or form, figure; mere show," from Anglo-French apparaunce, Old French aparance "appearance, display, pomp" (13c.), from Latin apparentia, abstract noun from aparentem, past participle of apparere (see appear). Meaning "semblance" is recorded from early 15c.; that of "action of coming into view" is mid-15c. Phrase keep up appearances attested from 1760 (save appearances in same sense is 1711).
appeasable (adj.): 1540s; see appease + -able. Related: Appeasably.
appease (v.): c.1300 "to reconcile," from Anglo-French apeser, Old French apaisier "to pacify, make peace, appease, be reconciled, placate" (12c.), from the phrase a paisier "bring to peace," from a "to" (see ad-) + pais, from Latin pacem (nominative pax) "peace" (see peace). Related: Appeased; appeasing.
appeasement (n.): mid-15c., "pacification," from Middle French apeisement, Old French apaisement "appeasement, calming," noun of action from apaisier (see appease). First recorded 1919 in international political sense; not pejorative until failure of Chamberlain's policy toward Germany in 1939 (Methods of appeasement was Chamberlain's description of his policy).
appeaser (n.): mid-15c., agent noun from appease (v.). Political sense attested from 1940.
appellant (n.): late 14c., Anglo-French, from Old French apelant, noun use of present participle of apeler, from Latin appellare (see appeal).
appellate (adj.): "pertaining to appeals," 1726, from Latin appellatus, past participle of appellare (see appeal). Appellate jurisdiction is in Blackstone (1768).
appellation (n.): late 15c., "action of appealing" (to a higher authority), from Old French apelacion (13c.), from Latin appellationem (nominative appellatio) "an addressing, accosting; an appeal; a name, title," noun of action from past participle stem of appellare (see appeal). Meaning "designation, name given to a person, thing, or class" is from mid-15c., from a sense also found in Middle French appeler.
appellative (adj.): mid-15c., from Latin appellativus, from appellat-, past participle stem of appellare (see appeal). As a noun, attested from 1590s.
appellee (n.): 1530s, from Anglo-French (late 14c.), from Old French apelé (Modern French appelé) "accused, defendant," noun use of past participle of appeler "to call, address;" see appeal + -ee.
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 from appendix + -ectomy.
appendices (n.): proper Latin plural of appendix.
appendicitis (n.): 1886, from Latin stem of appendix + -itis.
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 (cf. Old Saxon, Old Frisian, Dutch appel, Old Norse eple, Old High German apful, German Apfel), from PIE *ab(e)l "apple" (cf. Gaulish avallo "fruit;" Old Irish ubull, Lithuanian obuolys, Old Church Slavonic jabloko "apple"), but the exact relation and original sense of these is uncertain (cf. 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 (e.g. 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" (cf. 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.
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.