Online Etymology Dictionary

pick (n.1): c. 1200, "pointed tool for breaking up rock or ground," variant of pike (n.4). Meaning "sharp tool" is from mid-14c.
pick (n.2): mid-15c., "a blow with a pointed instrument," from pick (v.). Meaning "plectrum for a guitar, lute, etc." is from 1895; as a type of basketball block, from 1951; meaning "choicest part or example" is first recorded 1760.
pick up (v.): early 14c. as a verbal phrase, "lift and take," from pick (v.) + up (adv.). Of persons, "make acquaintance or take along," especially for sexual purposes, 1690s. Meaning "cause (someone) to revive" is from 1857. Sense of "tidy up" is from 1861; that of "arrest" is from 1871; meaning "gain speed" is from 1922; meaning "to pay" (a check, tab, etc.) is from 1945. Pick-me-up "stimulating alcoholic drink" is attested from 1867.
pickaxe (n.): also pick-axe, early 15c., folk etymology alteration (by influence of axe) of Middle English picas (mid-13c.), via Anglo-French piceis, Old French pocois (11c.) and directly from Medieval Latin picosa "pick," related to Latin picus "woodpecker" (see pie (n.2)).
picked (adj.): "chosen for excellence," 1540s, past participle adjective from pick (v.).
pickelhaube (n.): Prussian spiked helmet, 1875, from German Pickelhaube, from pickel "(ice)pick, pickaxe," + haube "hood, bonnet." But the German word is attested 17c., long before the helmet type came into use, and originally meant simply "helmet;" Palmer ("Folk-Etymology") reports a German theory (Andresen) that it is a folk-etymology: "as if from Pickel and haube, a cap or coif[;] more correctly written Biekelhaube, [it] is for Beckelhaube, a word most probably derived from becken, a basin."
picker (n.): 1520s, "one who steals;" literal use "one who picks" is from 1660s; agent noun from pick (v.). From 1923 as "one who plays the banjo." Picker-upper attested from 1936.
pickerel (n.): "young pike," late 13c., from pike (n.3), the fish, with French pejorative suffix -rel; perhaps formed in Anglo-French.
picket (n.): 1680s, "pointed stake (for defense against cavalry, etc.)," from French piquet "pointed stake," from piquer "to pierce" (see pike (n.2)). Sense of "troops posted to watch for enemy" first recorded 1761; that of "striking workers stationed to prevent others from entering a factory" is from 1867. Picket line is 1856 in the military sense, 1945 of labor strikes.
picket (v.): 1745, "to enclose with pickets," from picket (n.). The sense in labor strikes, protests, etc., is attested from 1867. Related: Picketed; picketing.
pickle (n.): c. 1400, probably from Middle Dutch pekel "pickle, brine," or related words in Low German and East Frisian (Dutch pekel, East Frisian päkel, German pökel), of uncertain origin or original meaning. Klein suggests the name of a medieval Dutch fisherman who developed the process. Originally a sauce served with meat or fowl; meaning "cucumber preserved in pickle" first recorded 1707, via use of the word for the salty liquid in which meat, etc. was preserved (c. 1500). Figurative sense of "sorry plight" first recorded 1560s, from the time when the word still meant a sauce served on meat about to be eaten. Meaning "troublesome boy" is from 1788, perhaps from the notion of being "imbued" with roguery.
pickle (v.): 1550s, from pickle (n.). Related: Pickled; pickling.
pickled (adj.): "drunk," American English slang, 1900, figurative past participle adjective from pickle (v.).
picklock (n.): 1550s, from pick (v.) + lock (n.).
pickpocket (n.): also pick-pocket, 1590s, from pick (v.) + pocket (n.). Earlier was pick-purse (late 14c.). As a verb from 1670s.
pickup (n.): also pick-up, "that which is picked up," 1848; see pick up (v.). As "act of picking up" from 1882. Meaning "capacity for acceleration" is from 1909; that of "recovery" is from 1916. In reference to a game between informal teams chosen on the spot, from 1905 (as an adjective in this sense by 1936).

Meaning "small truck used for light loads," 1937, is shortened from pickup truck (pickup body is attested from 1928). The notion probably being of a vehicle for use to "pick up" (feed, lumber, etc.) and deliver it where it was needed.
picky (adj.): 1867, from pick (v.) + -y (2). Related: Pickiness. The earliest recorded uses are in reference to eating.
picnic (n.): 1748 (in Chesterfield's "Letters"), but rare before c. 1800 as an English institution; originally a fashionable pot-luck social affair, not necessarily out of doors; from French piquenique (1690s), perhaps a reduplication of piquer "to pick, peck," from Old French (see pike (n.2)), or the second element may be nique "worthless thing," from a Germanic source. Figurative sense of "something easy" is from 1886. Picnic table recorded from 1926, originally a folding table.
picnic (v.): "go on a picnic," 1842, from picnic (n.). Related: Picnicked; picnicking. The -k- is inserted to preserve the "k" sound of -c- before a suffix beginning in -i-, -y-, or -e- (compare traffic/trafficking, panic/panicky, shellac/shellacked).
pico-: word-forming element used in making names for very small units of measure, 1915 (formally adopted c. 1952 as a scientific prefix meaning "one trillionth"), from Spanish pico "a little over, a small balance," literally "sharp point, beak," of Celtic origin (compare Gaulish beccus "beak").
picosecond (n.): 1966, from pico- + second (n.).
Pict (n.): an ancient people of Great Britain, late 14c., from Late Latin Picti (late 3c., probably a nickname given them by Roman soldiers), usually taken as derived from picti "painted," but probably ultimately from the Celtic name of the tribe, perhaps Pehta, Peihta, literally "the fighters" (compare Gaulish Pictavi, a different people, who gave the name to the French city of Poitiers). They painted and tattooed themselves, which may have suggested a Roman folk-etymology alteration of the name. The Old English name for the people was Peohtas.
In Scottish folk-lore the Pechts are often represented as a dark pygmy race, or an underground people; and sometimes identified with elves, brownies, or fairies. [OED]
Related: Pictish; Pictland.
pictogram (n.): 1910, from stem of Latin pictus "painted," past participle of pingere "to paint" (see paint (v.)) + -gram.
pictograph (n.): "picture or symbol representing an idea," 1851, from Latin pictus "painted," past participle of pingere "to paint" (see paint (v.)) + -graph "something written." First used in reference to American Indian writing. Related: Pictography.
pictorial (adj.): 1640s, from Latin pictorius "of a painter," from pictor "painter," from past participle stem of pingere "to make pictures" (see paint (v.)) + -al (1). The noun meaning "journal in which pictures are the main feature" is first recorded 1844. Related: Pictorially.
picturable (adj.): 1796, from picture (v.) + -able. Related: Picturably.
picture (n.): early 15c., "drawing, painting," from Latin pictura "painting," from pictus, past participle of pingere "to make pictures, to paint, to embroider," (see paint (v.)). Picture window is from 1938. Picture post-card first recorded 1899. Phrase every picture tells a story first attested 1900, in advertisements for an illustrated life of Christ. To be in (or out of) the picture in the figurative sense dates to 1900.

Expression a picture is worth a thousand words, attested from 1918, probably was from the publication trade (the notion that a picture was worth 1,000 words is in printers' publications by 1911). The phrase also was in use in the form worth a million words, the form used by American newspaper editor Arthur Brisbane (1864-1936) in an editorial much-read c. 1916 titled "What is a Good Newspaper" in the "New York Evening Journal." In part it read, "After news and humor come good pictures. In this day of hurry we learn through the eye, and one picture may be worth a million words." It seems to have emerged into general use via the medium of advertising (which scaled down the number and also gave the expression its spurious origin story as "a Japanese proverb" or some such thing, by 1919). Earlier various acts or deeds (and in one case "the arrow") were said to be worth a thousand words.
picture (v.): late 15c. in the literal sense; 1738 in the mental sense, from picture (n.). Related: Pictured; picturing.
picturephone (n.): 1964, from picture (n.) + phone (n.1).
pictures (n.): "movies," 1912, short for moving pictures.
picturesque (adj.): 1703, on pattern of French pittoresque, a loan-word from Italian pittoresco, literally "pictorial" (1660s), from pittore "painter," from Latin pictorem (nominative pictor); see painter (n.1). As a noun from 1749. Related: Picturesquely; picturesqueness.
piddle (v.): 1540s, "to peddle, to work in a trifling way," of uncertain origin, apparently a frequentative form. Meaning "to pick at one's food" is from 1610s; that of "urinate" is from 1796. Related: Piddled; piddler; piddling.
piddling (adj.): "insignificant, trifling," 1550s, past participle adjective from piddle (v.).
pidgin (n.): 1876, from pigeon English (1859), the reduced form of the language used in China for communication with Europeans, from pigeon (1826), itself a pidgin word, representing a Chinese pronunciation of business. Meaning extended 1891 to "any simplified language."
pie (n.1): "pastry," mid-14c. (probably older; piehus "bakery" is attested from late 12c.), from Medieval Latin pie "meat or fish enclosed in pastry" (c. 1300), perhaps related to Medieval Latin pia "pie, pastry," also possibly connected with pica "magpie" (see pie (n.2)) on notion of the bird's habit of collecting miscellaneous objects. Figurative of "something to be shared out" by 1967.

According to OED, not known outside English, except Gaelic pighe, which is from English. In the Middle Ages, a pie had many ingredients, a pastry but one. Fruit pies began to appear c. 1600. Figurative sense of "something easy" is from 1889. Pie-eyed "drunk" is from 1904. Phrase pie in the sky is 1911, from Joe Hill's Wobbly parody of hymns. Pieman is not attested earlier than the nursery rhyme "Simple Simon" (c. 1820). Pie chart is from 1922.
pie (n.2): "magpie," mid-13c. (late 12c. as a surname), from Old French pie (13c.), from Latin pica "magpie" (see magpie). In 16c., a wily pie was a "cunning person."
pie (n.3): also pi, printers' slang for "a mass of type jumbled together" (also pi, pye), 1650s, perhaps from pie (n.1) on notion of a "medley," or pie (n.2); compare pica (n.1). As a verb from 1870. Related: Pied.
piebald (adj.): "of two different colors," 1580s, formed from pie (n.2) "magpie" + bald in its older sense of "spotted, white;" in reference to the black-and-white plumage of the magpie. Hence, "of mixed character, mongrel." Technically only of black-and-white colorings.
piece (n.): c. 1200, "fixed amount, measure, portion," from Old French piece "piece, bit portion; item; coin" (12c.), from Vulgar Latin *pettia, probably from Gaulish *pettsi (compare Welsh peth "thing," Breton pez "piece, a little"), perhaps from an Old Celtic base *kwezd-i-, from PIE root *kwezd- "a part, piece" (source also of Russian chast' "part"). Related: Pieces.

Sense of "portable firearm" first recorded 1580s; that of "chessman" is from 1560s. Meaning "person regarded as a sex object" is first recorded 1785 (compare piece of ass, human beings colloquially called piece of flesh from 1590s; also compare Latin scortum "bimbo, anyone available for a price," literally "skin"). Meaning "a portion of a distance" is from 1610s; that of "literary composition" dates from 1530s. Piece of (one's) mind is from 1570s. Piece of work "remarkable person" echoes Hamlet. Piece as "a coin" is attested in English from 1570s, hence Piece of eight, old name for the Spanish dollar (c. 1600) of the value of 8 reals.
PIECE. A wench. A damned good or bad piece; a girl who is more or less active and skilful in the amorous congress. Hence the (Cambridge) toast, may we never have a PIECE (peace) that will injure the constitution. ["Dictionary of Buckish Slang, University Wit and Pickpocket Eloquence," London, 1811]
piece (v.): "to mend by adding pieces," late 14c., from piece (n.). Sense of "to join, unite, put together" is from late 15c. Related: Pieced; piecing.
piece de resistance (n.): 1831, from French pièce de résistance, originally "the most substantial dish in a meal." Lit. "piece of resistance;" there seems to be disagreement as to the exact signification.
piecemeal (adv.): c. 1300 (originally two words), from piece (n.) + Middle English meal "fixed time, period of time, occasion," from Old English mælum "at a time," dative plural of mæl "appointed time, food served" (see meal (n.1)). The second element once was more common, as in Old English styccemælum "bit by bit," gearmælum "year by year." One-word form from 15c.
piecework (n.): also piece-work, 1540s, from piece (n.) + work (n.).
pied (adj.): late 14c., as if it were the past participle of a verb form of Middle English noun pie "magpie" (see pie (n.2)), in reference to the bird's black and white plumage. Earliest use is in reference to the pyed freres, an order of friars who wore black and white. Also in pied piper (1845, in Browning's poem based on the German legend; used allusively by 1939).
pied a terre (n.): "small town house or rooms used for short residences," 1829, French, pied à terre, literally "foot on the ground."
piedmont (n.): name given to the fertile upland region along the eastern slope of the Appalachians, 1755, originally piemont, from Italian Piemonte, literally "mountain foot," name of the region at the foot of the Alps in northern Italy (see Piedmont). With -d- added by 1855. Applied to similar features of other mountain ranges by 1860.
Piedmont: region in northern Italy, from Old Italian pie di monte "foot of the mountains," from pie "foot" (see foot (n.)) + monte "mountain" (see mount (n.)). Related: Piedmontese.
piepowder (n.): early 13c., "wayfarer, itinerant merchant, etc.," folk etymology alteration of Old French pie pouldre or Medieval Latin pede-pulverosus, both literally "dusty-footed" (see foot (n.) + powder (n.)).
pier (n.): mid-12c., "support of a span of a bridge," from Medieval Latin pera, of unknown origin, perhaps from Old North French pire "a breakwater," from Vulgar Latin *petricus, from Latin petra "rock" (see petrous), but OED is against this. Meaning "solid structure in a harbor, used as a landing place for vessels," is attested from mid-15c.
pierce (v.): late 13c. "make a hole in; force one's way through," from Anglo-French perser, Old French percier "pierce, transfix, drive through" (12c., Modern French percer), probably from Vulgar Latin *pertusiare, frequentative of Latin pertusus, past participle of pertundere "to thrust or bore through," from per- "through" (see per) + tundere "to beat, pound," from PIE *tund-, from root *(s)teu- "to push, strike, knock, beat, thrust" (see obtuse). Related: Pierced; piercing.