Online Etymology Dictionary

postnatal (adj.): 1831, from post- + natal.
postpone (v.): c. 1500, from Latin postponere "put after; esteem less; neglect; postpone," from post "after" (see post-) + ponere "put, place" (see position (n.)). Related: Postponed; postponing.
postponement (n.): 1770, from postpone + -ment.
postposition (n.): "act of placing after, 1630s, from post- + position (n.). Related: Postpositional.
postprandial (adj.): also post-prandial, 1820, from post- "after" + Latin prandium "luncheon" (usually bread, fish, or cold meat, taken around noon), from *pram "early" (from PIE *pre-, variant of root per- (1) "forward, through;" see per) + edere "to eat" (see edible) + -al (1).
postscript (n.): 1550s, from Latin post scriptum "written after," from neuter past participle of Latin postscribere "write after," from post "after" (see post-) + scribere "to write" (see script (n.)).
postulant (n.): 1759, from French postulant "applicant, candidate," literally "one who asks," from Latin postulantem (nominative postulans), present participle of postulare "to ask, demand" (see postulate (v.)).
postulate (v.): 1530s, "nominate to a church office," from Medieval Latin postulatus, past participle of postulare "to ask, demand; claim; require," probably formed from past participle of Latin poscere "ask urgently, demand," from *posk-to-, Italic inchoative of PIE root *prek- "to ask questions" (source also of Sanskrit prcchati, Avestan peresaiti "interrogates," Old High German forskon, German forschen "to search, inquire"). Use in logic dates from 1640s, borrowed from Medieval Latin.
postulate (n.): 1580s, "a request, demand," from Latin postulatum "demand, request," properly "that which is requested," noun use of neuter past participle of postulare (see postulate (v.)). The sense in logic of "self-evident proposition" is from 1640s. The earlier noun in English was postulation (c. 1400).
posture (n.): c. 1600, from French posture (16c.), from Italian postura "position, posture," from Latin positura "position, station," from postulus from past participle stem of ponere "to put, place" (see position (n.)).
posture (v.): 1620s, literal, from posture (n.). The figurative sense of "take up an artificial mental position" is attested from 1877. Related: Postured; posturing.
Posturpedic (n.): trademark name (Sealy, Inc., Chicago, U.S.A.) for a brand of mattress, filed in 1951; from posture (n.) + second element from orthopedic.
postwar (adj.): also post-war, 1906, in reference to the U.S. Civil War, a hybrid from post- + war (n.). Compare post-bellum.
posy (n.): also posey, 1530s, "line of verse engraved on the inner surface of a ring," from poesy "poetry; a passage of poetry," which is recorded in this sense from early 15c. Meaning "flower, bouquet" first recorded 1570s, from notion of the language of flowers.
pot (n.1): "vessel," from late Old English pott and Old French pot "pot, container, mortar" (also in erotic senses), both from a general Low Germanic (Old Frisian pott, Middle Dutch pot) and Romanic word from Vulgar Latin *pottus, of uncertain origin, said by Barnhart and OED to be unconnected to Late Latin potus "drinking cup." Celtic forms are said to be borrowed from English and French.

Slang meaning "large sum of money staked on a bet" is attested from 1823. Pot roast is from 1881; phrase go to pot (16c.) suggests cooking. In phrases, the pot calls the kettle black-arse is from c. 1700; shit or get off the pot is traced by Partridge to Canadian armed forces in World War II.
pot (n.2): "marijuana," 1938, probably a shortened form of Mexican Spanish potiguaya "marijuana leaves."
pot (v.): "to put in a pot," 1610s, from pot (n.1). Related: Potted; potting. Earlier it meant "to drink from a pot" (1590s).
pot-bellied (adj.): also potbellied, 1650s, from pot (n.1) + bellied. As a type of stove from 1973.
pot-belly (n.): 1714, from pot (n.1) + belly (n.). Pot-belly stove, so called for its shape, attested from 1943.
pot-holder (n.): also potholder, the cloth variety so called by 1902, from pot (n.1) + holder.
pot-pie (n.): also potpie, 1823, American English, from pot (n.1) + pie (n.).
potable (adj.): early 15c., from Old French potable (14c.) and directly from Late Latin potabilis "drinkable," from Latin potare "to drink" (see potion).
potage (n.): "thick soup," 1560s, from French potage "soup, broth" (see pottage, which is an earlier English borrowing of the same French word).
potamo-: word-forming element meaning "river," from comb. form of Greek potamos "river," perhaps literally "rushing water," from PIE *pet- "to rush, to fly" (see petition).
potamology (n.): "the study of rivers," 1829, from potamo- + -logy.
potash (n.): 1751, earlier -pot-ashes (1640s), a loan-translation of older Dutch potaschen, literally "pot ashes" (16c.); so called because it was originally obtained by soaking wood ashes in water and evaporating the mixture in an iron pot. Compare German Pottasche, Danish potaske, Swedish pottaska, all also from Dutch. See also potassium. French potasse (1570s), Italian potassa are Germanic loan-words. The original plural was pot-ashes.
potassium (n.): metallic element, 1807, coined by English chemist Sir Humphrey Davy (1778-1829) from Modern Latin potassa, Latinized form of potash (q.v.). Davy first isolated it from potash. Symbol K is from Latin kalium "potash," from Arabic al-qaliy "the ashes, burnt ashes" (see alkali).
potation (n.): early 15c., from Old French potacion, from Latin potationem (nom. potatio) "a drinking; poisonous drink, potion," noun of action from past participle stem of potare "to drink" (see potion).
potato (n.): 1560s, from Spanish patata, from a Carib language of Haiti batata "sweet potato." Sweet potatoes were first to be introduced to Europe; in cultivation in Spain by mid-16c.; in Virginia by 1648. Early 16c. Portuguese traders carried the crop to all their shipping ports and the sweet potato was quickly adopted from Africa to India and Java.

The name later (1590s) was extended to the common white potato, from Peru, which was at first (mistakenly) called Virginia potato, or, because at first it was of minor importance compared to the sweet potato, bastard potato. Spanish invaders in Peru began to use white potatoes as cheap food for sailors 1530s. The first potato from South America reached Pope Paul III in 1540; grown in France at first as an ornamental plant. According to popular tradition, introduced to Ireland 1565 by John Hawkins. Brought to England from Colombia by Sir Thomas Herriot, 1586.

German kartoffel (17c.) is a dissimilation from tartoffel, ultimately from Italian tartufolo (Vulgar Latin *territuberem), originally "truffle." Frederick II forced its cultivation on Prussian peasants in 1743. The French is pomme de terre, literally "earth-apple;" a Swedish dialectal word for "potato" is jordpäron, literally "earth-pear."

Colloquial pronunciation tater is attested in print from 1759. Potato chip (n.) attested from 1879. To drop (something) like a hot potato is from 1824. Children's counting-out rhyme that begins one potato, two potato first recorded 1885 in Canada. Slang potato trap "mouth" attested from 1785.
potboiler (n.): also pot-boiler, 1864 in the figurative literary sense, from pot (n.1) + agent noun from boil (v.). The notion is of something one writes solely to put food on the table.
poteen (n.): "illicit whiskey," 1812, from Irish poitin "little pot," suggesting distillation in small quantities, from English pot (n.1) "vessel" + diminutive suffix -in, -een.
Potemkin: in reference to Grigory Aleksandrovich Potemkin (1739-1791), favorite of Catherine II of Russia, especially in reference to the sham villages supposedly erected under his orders for the empress' tour of Crimea (1787) to create an impression of prosperity and progress. The silent film "Battleship Potemkin" dates from 1925, depicting (with elaboration) events of 1905 and the mutiny of a Russian battleship named for the Tsarist minister.
potence (n.): "potency," early 15c., from Old French potence "power," from Latin potentia (see potent).
potency (n.): mid-15c., from Latin potentia "power," from potentem "potent" (see potent).
potent (adj.): early 15c., from Latin potentem (nominative potens) "powerful," present participle of *potere "be powerful," from potis "powerful, able, capable; possible;" of persons, "better, preferable; chief, principal; strongest, foremost," from PIE root *poti- "powerful; lord" (source also of Sanskrit patih "master, husband," Greek posis, Lithuanian patis "husband"). Meaning "having sexual power" is first recorded 1899.
potentate (n.): c. 1400, from Old French potentat and directly from Late Latin potentatus "a ruler," also "political power," from Latin potentatus "might, power, rule, dominion," from potentem (nominative potens) "powerful" (see potent).
potential (adj.): late 14c., "possible" (as opposed to actual), from Old French potenciel and directly from Late Latin potentialis "potential," from Latin potentia "power, might, force;" figuratively "political power, authority, influence," from potens "powerful" (see potent). The noun, meaning "that which is possible," is first attested 1817, from the adjective.
potentiality (n.): 1620s, from potential + -ity, or else from Medieval Latin potentialitas, from potentialis (see potential).
potentially (adv.): early 15c., "in possibility," opposed to actually; from potential + -ly (2).
potentiate (v.): 1817 (Coleridge) "endow with power," from Latin potentia "power, might, force" (see potential) + -ate (2) on model of German potenzieren. Related: Potentiated; potentiating; potentiation.
potentiometer (n.): 1868, a hybrid formed from comb. form of Latin potentia "power" (see potential) + Greek-derived -meter.
pothead (n.): also pot-head "chronic marijuana user," 1967, from pot (n.2) + head (n.). Earlier it meant "stupid person" (1530s), from pot (n.1).
pother (n.): 1590s, "disturbance, commotion," of unknown origin. Meaning "mental trouble" is from 1640s; verb sense of "to fluster" is attested from 1690s.
pothole (n.): also pot-hole, 1826, originally a geological feature in glaciers and gravel beds, from Middle English pot "a deep hole for a mine, or from peat-digging" (late 14c.), now generally obsolete, but preserved in Scotland and northern England dialect; perhaps ultimately related to pot (n.1) on notion of "deep, cylindrical shape." Applied to a hole in a road from 1909.
potion (n.): c. 1300, pocioun "medicinal drink," from Old French pocion "potion, draught, medicine" (12c.), from Latin potionem (nominative potio) "a potion, a drinking," also "poisonous draught, magic potion," from potus, irregular past participle of potare "to drink," from PIE root *po(i)- "to drink" (source also of Sanskrit pati "drinks," panam "beverage;" Greek pinein "to drink," poton "that which one drinks," potos "drinking bout;" Old Church Slavonic piti "to drink," pivo "beverage"). Potus as a past participle adjective in Latin meant "drunken."
potlatch (n.): 1845, "a gift," from Chinook jargon pot-latch, "a gift," from Nootka (Wakashan) patshatl "giving, gift." Later (1865) in sense "ceremony in which gifts are exchanged."
potluck (n.): also pot-luck, 1590s, from pot (n.1) + luck; with notion of "one's luck or chance as to what may be in the pot." As an adjective from 1775.
Potomac: river in eastern U.S., from Algonquian Patowmeck, originally the name of a native village in Virginia, perhaps literally "something brought."
potpourri (n.): also pot-pourri, 1610s, "mixed meats served in a stew," from French pot pourri "stew," literally "rotten pot" (loan-translation of Spanish olla podrida), from pourri, past participle of pourrir "to rot," from Vulgar Latin *putrire, from Latin putrescere "grow rotten" (see putrescent). Notion of "medley" led to meaning "mixture of dried flowers and spices," first recorded in English 1749. Figurative sense (originally in music) of "miscellaneous collection" is recorded from 1855.
Potsdam: town in Germany, first recorded 993 as Poztupimi; the name is Slavic, the first element is po "by near," the second element evidently was influenced by Dutch names in -dam. The Potsdam Conference of the victorious Allies in World War II was held July 17-Aug. 2, 1945, to decide the fate of Germany.