Online Etymology Dictionary

pavilion (n.): c.1200, "large, stately tent," from Old French paveillon "large tent; butterfly" (12c.), from Latin papilionem (nominative papilio) "butterfly, moth," in Medieval Latin "tent" (see papillon); the type of tent so called on resemblance to wings. Meaning "open building in a park, etc., used for shelter or entertainment" is attested from 1680s.
Pavlovian (adj.): 1931, from the theories, experiments, and methods of Russian physiologist Ivan Petrovich Pavlov (1849-1936), especially in connection with the salivary reflexes of dogs in response to mental stimulus of the sound of a bell (attested from 1911, in Pavloff [sic] method).
paw (n.): c.1300, from Old French powe, poe "paw, fist," of uncertain origin. Evidence points to a Gallo-Romance root form *pauta which probably is related to the source of patten.
paw (v.): "use the hands roughly," c.1600, from paw (n.). Related: Pawed; pawing. Middle English had pawen "to touch or strike with the paw" (c.1400).
pawl (n.): "bar preventing a capstan from recoiling" (nautical) 1620s, of unknown origin; perhaps from French pal "stake" [OED] or épaule "shoulder" [Klein].
pawn (n.1): "something left as security," late 15c. (mid-12c. as Anglo-Latin pandum), from Old French pan, pant "pledge, security," also "booty, plunder," perhaps from Frankish or some other Germanic source (cf. Old High German pfant, German Pfand, Middle Dutch pant, Old Frisian pand "pledge"), from West Germanic *panda, of unknown origin.

The Old French word is identical to pan "cloth, piece of cloth," from Latin pannum (nominative pannus) "cloth, piece of cloth, garment" and Klein's sources feel this is the source of both the Old French and West Germanic words (perhaps on the notion of cloth used as a medium of exchange).
pawn (n.2): lowly chess piece, late 14c., from Anglo-French poun, Old French peon, earlier pehon, from Medieval Latin pedonem "foot soldier," from Late Latin pedonem (nominative pedo) "one going on foot," from Latin pes (genitive pedis) "foot" (see foot (n.)). The chess sense was in Old French by 13c. Figurative use, of persons, is from 1580s.
pawn (v.): "to give (something) as security in exchange for," 1560s, from pawn (n.1). Related: Pawned; pawning.
pawnbroker (n.): 1680s, from pawn (n.1) + broker (n.).
Pawnee: Indian tribes of the Caddoan family, formerly inhabiting the plains of Nebraska, 1778, from Canadian French pani, from a Siouan language, e.g. Oto panyi.
pawnshop (n.): also pawn-shop, by 1763, from pawn (n.1) + shop (n.).
pawpaw (n.): see papaw.
pax (n.): mid-15c., "kiss of peace," from Latin pax (genitive pacis) "peace," in Ecclesiastical Latin, "kiss of peace" (see peace). Capitalized, Pax was the name of the Roman goddess of peace. Used by 1933 with adjectives from national names, on model of Pax Romana (e.g. Pax Britannica, 1872; Pax Americana, 1886, with reference to Latin America).
pay (v.): c.1200, "to appease, pacify, satisfy," from Old French paier "to pay, pay up" (12c., Modern French payer), from Latin pacare "to please, pacify, satisfy" (in Medieval Latin especially "satisfy a creditor"), literally "make peaceful," from pax (genitive pacis) "peace" (see peace). Meaning "to give what is due for goods or services" arose in Medieval Latin and was attested in English by early 13c.; sense of "please, pacify" died out in English by 1500. Sense of "suffer, endure" (a punishment, etc.) is first recorded late 14c. Related: Paid; paying.
pay (n.): c.1300, "satisfaction, liking, reward," from pay (v.), or else from Old French paie "payment, recompense," from paier. Meaning "money given for labor or services, wages" is from late 14c.
payable (adj.): late 14c., "to be paid," from pay (v.) + -able or from Old French paiable.
payback (n.): also pay-back, 1946, "net return on profits from an investment," from pay (v.) + back (adj.). Meaning "revenge" is attested from 1957.
paycheck (n.): also pay-check, 1894, from pay (n.) + check (n.).
payday (n.): also pay-day, 1520s, from pay (n.) + day.
paydirt (n.): also pay dirt, "profit, success," 1873, from pay (n.) + dirt (n.); a word from mining, where it was used in a literal sense from 1856.
payee (n.): 1758, from pay (v.) + -ee.
payer (n.): "person who pays" (originally wages, late 14c., later taxes, early 15c.), from Old French paiere (13c.), agent noun from paier (see pay (v.)).
payload (n.): also pay-load, 1917, from pay + load (n.). Originally the part of a truck's (later an aircraft's) load from which revenue is derived (passengers, cargo, mail); figurative sense of "bombs, etc. carried by a plane or missile" is from 1936.
payment (n.): late 14c., from Old French paiement (13c.), from paiier (see pay (v.)).
paynim (n.): mid-13c., "heathen lands," from Old French paienime, paienisme "heathen, pagan; Saracen lands or culture or faith," from Late Latin paganismus "heathendom" (Augustine), from paganus "heathen" (see pagan); mistaken meaning "a heathen person" (late 14c., also in Old French) is via phrases such as paynim lands.
payoff (n.): also pay-off, 1905, "winnings from gambling," from pay (v.) + off. Meaning "graft, bribes" first attested 1930. Phrase to pay off "be profitable" is first recorded 1937.
payola (n.): "graft" (especially to disc jockeys from record companies to play their music), 1938 (in a "Variety" headline), from pay off "bribery" (underworld slang from 1930) + ending from Victrola, etc. (see pianola). Cf. also plugola (1959), from plug (n.) in the advertising sense.
payor (n.): 1817, agent noun in Latin form from pay (v.). Chiefly legalese.
payout (n.): 1904, from pay (v.) + out. Originally in reference to oil wells that produced enough to justify the expense of drilling them.
Paypal (n.): e-commerce money transfer business, formed 2000 by merger of earlier firms.
payphone (n.): also pay-phone, 1906, from pay (v.) + phone (n.).
payroll (n.): 1740, from pay (v.) + roll (n.); "total amount paid to employees over a period," hence, via records-keeping, "list of employees receiving pay."
PBS: abbreviation of Public Broadcasting Service, 1970, America English. It succeeded National Educational Television (NET).
pcb: 1966, from polychlorinated biphenyl.
pcp: 1977, from phenocyclidine.
pda: by 1992, initialism for personal digital assistant.
pdf: by 1992, initialism for portable document format, a generic term.
PE: 1956 as an abbreviation of physical education (see physical).
pea (n.): early or mid-17c., false singular from Middle English pease (plural pesen), which was both single and collective (e.g. wheat, corn) but the "s" sound was mistaken for the plural inflection. From Old English pise (West Saxon), piose (Mercian) "pea," from Late Latin pisa, variant of Latin pisum "pea," from Greek pison "the pea," perhaps of Thracian or Phrygian origin [Klein].

In Southern U.S. and the Caribbean, used of other legumes as well. Pea soup is first recorded 1711 (pease-soup); applied to London fogs since at least 1849. Pea-shooter attested from 1803.
pea jacket (n.): 1721, loan-translation of North Frisian pijekkat, from Dutch pijjekker, from pij "coarse woolen cloth" + jekker "jacket." Middle English had pee "coat of coarse, thick wool" (late 15c.). Related: Pea-coat.
peace (n.): mid-12c., "freedom from civil disorder," from Anglo-French pes, Old French pais "peace, reconciliation, silence, permission" (11c., Modern French paix), from Latin pacem (nominative pax) "compact, agreement, treaty of peace, tranquility, absence of war" (source of Provençal patz, Spanish paz, Italian pace), from PIE *pag-/*pak- "fasten," related to pacisci "to covenant or agree" (see pact).

Replaced Old English frið, also sibb, which also meant "happiness." Modern spelling is 1500s, reflecting vowel shift. Sense in peace of mind is from c.1200. Used in various greetings from c.1300, from Biblical Latin pax, Greek eirene, which were used by translators to render Hebrew shalom, properly "safety, welfare, prosperity."

Sense of "quiet" is attested by 1300; meaning "absence or cessation of war or hostility" is attested from c.1300. As a type of hybrid tea rose (developed 1939 in France by Francois Meilland), so called from 1944. Native American peace pipe is first recorded 1760. Peace-officer attested from 1714. Peace offering is from 1530s. Phrase peace with honor first recorded 1607 (in "Coriolanus"). The U.S. Peace Corps was set up March 1, 1962. Peace sign, both the hand gesture and the graphic, attested from 1968.
peace-keeping (n.): also peacekeeping, 1961 in the international sense, from peace + keeping, verbal noun from keep (v.). Earlier "preservation of law and order" (mid-15c.). Related: Peace-keeper (1570s).
peaceable (adj.): early 14c., from Old French paisible "peaceful" (12c.), from pais (see peace). Related: Peacably.
peaceful (adj.): early 14c., "inclined to peace, friendly, pacific," from peace + -ful. Meaning "tranquil, calm, full of peace" is from mid-14c. In reference to nonviolent methods of effecting social change, it is attested from 1876. Related: Peacefully; peacefulness. Peaceful coexistence (1920) originally was in regard to Soviet policy toward the capitalist West.
peacemaker (n.): early 15c., from peace + maker.
peacenik (n.): 1962, from peace + -nik. An earlier equivalent was peacemonger (1808).
peacetime (n.): also peace-time, 1550s, from peace + time (n.).
peach (n.): c.1400 (late 12c. as a surname), from Old French pesche "peach, peach tree" (Old North French peske, Modern French pêche), and directly from Medieval Latin pesca, from Late Latin pessica, variant of persica "peach, peach tree," from Latin malum Persicum, literally "Persian apple," translating Greek Persikon malon, from Persis "Persia" (see Persian).

In ancient Greek Persikos could mean "Persian" or "the peach." The tree is native to China, but reached Europe via Persia. By 1663 William Penn observed peaches in cultivation on American plantations. Meaning "attractive woman" is attested from 1754; that of "good person" is from 1904. Peaches and cream in reference to a type of complexion is from 1901. Peach blossom as a color is from 1702. Georgia has been the Peach State since 1939.
peach (v.): "to inform against," 1560s (earlier "to accuse, indict, bring to trial," mid-15c.), a shortening of appeach, an obsolete variant of impeach. Related: Peached; peaching.
peachy (adj.): 1590s, "resembling a peach" in some way, from peach (n.) + -y (2). Slang sense of "attractive" attested by 1900. Extended form peachy-keen recorded from 1953. Related: Peachiness.