Online Etymology Dictionary

pilchard (n.): fish of the herring family, 1540s, earlier pilcher (1520s), of unknown origin. The -d- is "excrescent" [OED].
pile (n.3): "soft, raised surface upon cloth," mid-14c., "downy plumage," from Anglo-French pyle or Middle Dutch pijl, both from Latin pilus "a hair" (source of Italian pelo, Old French pel). Phonological evidence rules out transmission of the English word via Old French cognate peil, poil. Meaning "nap upon cloth" is from 1560s.
pile (n.1): "mass, heap," early 15c., originally "pillar, pier of a bridge," from Middle French pile and directly from Latin pila "stone barrier, pillar, pier" (see pillar). Sense development in Latin from "pier, harbor wall of stones," to "something heaped up." In English, sense of "heap of things" is attested from mid-15c. (the verb in this sense is recorded from mid-14c.). The meaning "large building" (late 14c.) is probably the same word.
pile (n.2): "heavy pointed beam," from Old English pil "stake," also "arrow," from Latin pilum heavy javelin of the Roman foot soldier, literally "pestle" (source of Old Norse pila, Old High German pfil, German Pfeil "arrow"), of uncertain origin.
pile (v.): "to heap up," mid-14c.; see pile (n.1). Related: Piled; piling. Figurative verbal expression pile on "attack vigorously, attack en masse," is from 1894, American English.
pile-driver (n.): 1772 in literal sense, from pile (n.2) + driver. Figurative sense of "very strong hit" is recorded from 1858.
pile-up (n.): "multi-vehicle crash," 1929, from verbal phrase pile up, which is from 1849 as "accumulate," 1899 as "to wreck in a heap" (see pile (v.)).
pileated (adj.): 1728, from Latin pileatus "capped," from pileus "felt cap without a brim," from Greek pilos. Applied in natural history to certain birds and sea urchins.
piles (n.): "hemorrhoids," c. 1400, from Medieval Latin pili "piles," probably from Latin pila "ball" (see pill (n.)); so called from shape.
pilfer (v.): 1540s, from pilfer (n.) "spoils, booty," c. 1400, from Old French pelfre "booty, spoils" (11c.), of unknown origin, possibly related to pelf. Related: Pilfered; pilfering.
pilferage (n.): 1620s, from pilfer + -age.
pilgrim (n.): c. 1200, pilegrim, from Old French pelerin, peregrin "pilgrim, crusader; foreigner, stranger" (11c., Modern French pèlerin), from Late Latin pelegrinus, dissimilated from Latin peregrinus "foreigner" (source of Italian pellegrino, Spanish peregrino), from peregre (adv.) "from abroad," from per- "beyond" + agri, locative case of ager "country" (see acre).

Change of first -r- to -l- in most Romance languages by dissimilation; the -m appears to be a Germanic modification. Pilgrim Fathers "English Puritans who founded Plymouth colony" is first found 1799 (they called themselves Pilgrims from c. 1630, in reference to Hebrew xi:13).
pilgrimage (n.): late 13c., pelrimage; from pilgrim + -age and also from Old French pelrimage, pelerinage "pilgrimage, distant journey, crusade," from peleriner "to go on a pilgrimage." Modern spelling from early 14c.
Pilipino: 1936, from Tagalog form of obsolete Spanish Pilipino (see Filipino).
pill (n.): "small ball or round mass of medicine," c. 1400, from Middle Dutch or Middle Low German pille and Middle French pile, all from Latin pilula "pill," literally "little ball," diminutive of pila "a ball, playing ball," said to be related to pilus "hair" if the original notion was "hairball." Figurative sense "something disagreeable that must be swallowed" is from 1540s; slang meaning "boring person" is recorded from 1871. The pill "contraceptive pill" is from 1957.
pill (v.): 1736, "to dose on pills," from pill (n.). From 1882 as "to form into pills." Related: Pilled; pilling.
pillage (n.): late 14c., "act of plundering" (especially in war), from Old French pilage (14c.) "plunder," from pillier "to plunder, loot, ill-treat," possibly from Vulgar Latin *piliare "to plunder," probably from a figurative use of Latin pilare "to strip of hair," perhaps also meaning "to skin" (compare figurative extension of verbs pluck, fleece), from pilus "a hair" (see pile (n.3)).
pillage (v.): "plunder, despoil," 1590s, from pillage (n.). Related: Pillaged; pillaging. The earlier verb in English was simply pill (late Old English), which probably is from Latin pilare.
pillar (n.): c. 1200, from Old French piler "pillar, column, pier" (12c., Modern French pilier) and directly from Medieval Latin pilare, from Latin pila "pillar, stone barrier." Figurative sense of "prop or support of an institution or community" is first recorded early 14c. Phrase pillar to post is c. 1600, originally of tennis, exact meaning obscure.
pillbox (n.): also pill-box, "box for holding pills," 1730, from pill (n.) + box (n.). As a small round concrete machine gun nest, it came into use in World War I. As a type of hat, attested from 1958.
pillbug (n.): also pill-bug, 1841, from pill (n.) + bug (n.).
piller (n.): "plunderer," early 14c., from obsolete verb pill "to plunder, to pillage" (see pillage (v.)).
pillion (n.): kind of saddle, c. 1500, of Celtic origin (compare Irish pillin, Gaelic pillin), ultimately from Latin pellis "skin, pelt" (see film (n.)).
pillock (n.): 1530s, dialectal variant of Middle English pillicock (see cock (n.1)). Meaning "stupid person" is attested by 1967.
pillory (n.): late 13c. (attested in Anglo-Latin from late 12c.), from Old French pilori "pillory" (mid-12c.), related to Medieval Latin pilloria, of uncertain origin, perhaps a diminutive of Latin pila "pillar, stone barrier" (see pillar), but OED finds this proposed derivation "phonologically unsuitable."
pillory (v.): c. 1600, from pillory (n.). Figurative sense of "expose publicly to ridicule or abuse" is from 1690s. Related: Pilloried.
pillow (n.): Middle English pilwe, from Old English pyle "pillow," from West Germanic *pulwi(n) (source also of Old Saxon puli, Middle Dutch polu, Dutch peluw, Old High German pfuliwi, German Pfühl), an early borrowing (2c. or 3c.) from Latin pulvinus "little cushion, small pillow," of uncertain origin. Modern spelling is from mid-15c. Pillow fight (n.) attested from 1837; slang pillow talk (n.) first recorded 1939.
pillow (v.): 1620s, from pillow (n.). Related: Pillowed; pillowing.
pilon (n.): 1892, from Mexican Spanish, from Spanish pilón "sugar loaf."
pilot (n.): 1510s, "one who steers a ship," from Middle French pillote (16c.), from Italian piloto, supposed to be an alteration of Old Italian pedoto, which usually is said to be from Medieval Greek *pedotes "rudder, helmsman," from Greek pedon "steering oar," related to pous (genitive podos) "foot," from PIE root *ped- (1) "a foot" (see foot (n.)). Change of -d- to -l- in Latin ("Sabine -l-") parallels that in odor/olfactory; see lachrymose.

Sense extended 1848 to "one who controls a balloon," and 1907 to "one who flies an airplane." As an adjective, 1788 as "pertaining to a pilot;" from 1928 as "serving as a prototype." Thus the noun pilot meaning "pilot episode" (etc.), attested from 1962. Pilot light is from 1890.
pilot (v.): 1640s, "to guide, lead;" 1690s, "to conduct as a pilot," from pilot (n.) or from French piloter. Related: Piloted; piloting.
pilot-fish (n.): 1630s, from pilot (n.) + fish (n.). So called because they were thought to lead sharks to prey.
piloted (adj.): 1945, past participle adjective from pilot (v.).
pilsner (n.): type of pale, hoppy lager beer, 1877, after Pilsen, German town in Bohemia (Czech Plzen) where it first was brewed. Now designating a type, not an origin; pilsner from Plzen is Pilsner Urquell, from German Urquell "primary source." The place name is from Old Czech plz "damp, moist." Related: Pils.
Piltdown: village in Sussex, England, site where a fossil humanoid skull was said to have been found (1912), proved a fraud in 1953.
Pima: Uto-Aztecan people of Arizona, from Spanish, probably from native pi ma:c "(I) don't know," given in answer to some question long ago and mistaken by the Spaniards as a tribal name. Related: Piman.
pimento (n.): 1680s, pimiento (modern form from 1718), from Spanish pimiento "green or red pepper," also pimienta "black pepper," from Late Latin pigmenta, plural of pigmentum "vegetable juice," from Latin pigmentum "pigment" (see pigment (n.)). So called because it added a dash of color to food or drink.
[I]n med.L. spiced drink, hence spice, pepper (generally), Sp. pimiento, Fr. piment are applied to Cayenne or Guinea pepper, capsicum; in Eng. the name has passed to allspice or Jamaica pepper. [OED]
The piece of red sweet pepper stuffed in a pitted olive so called from 1918, earlier pimiento (1901), from Spanish. French piment is from Spanish.
pimp (n.): c. 1600, of unknown origin, perhaps from Middle French pimpant "alluring in dress, seductive," present participle of pimper "to dress elegantly" (16c.), from Old French pimpelorer, pipelorer "decorate, color, beautify." Weekley suggests Middle French pimpreneau, defined in Cotgrave [French-English Dictionary, 1611] as "a knave, rascall, varlet, scoundrell," but Liberman is against this.
Judging by such recorded meanings of pimp as 'helper in mines; servant in logging camps,' this word was originally applied to boys and servants. [Liberman]
The word also means "informer, stool pigeon" in Australia and New Zealand and in South Africa, where by early 1960s it existed in Swahili form impimpsi. Pimpmobile first recorded 1973 (six years before Popemobile).
PIMP. A male procurer, or cock bawd; also a small faggot used about London for lighting fires, named from introducing the fire to the coals. [Grose, "Dictionary of the Vulgar Tongue," London, 1785]
pimp (v.): 1630s (intransitive) "to act as a pimp," from pimp (n.). Related: Pimped; pimping.
pimpernel (n.): c. 1400, from Old French pimprenelle, earlier piprenelle (12c.) and directly from Medieval Latin pipinella name of a medicinal plant. This is perhaps from *piperinus "pepper-like" (so called because its fruits resemble peppercorns), a derivative of Latin piper "pepper" (see pepper (n.)); or else it is a corruption of bipinnella, from bipennis "two-winged." The Scarlet Pimpernel was the code name of the hero in an adventure novel of that name published 1905.
pimple (n.): late 14c. (early 14c. as a surname), of unknown origin; perhaps related to Old English pipligende "having shingles;" also compare Latin papula, papilla (see pap (n.2)). As a verb from c. 1600. Related: Pimples.
pimply (adj.): 1748, from pimple (n.) + -y (2). Related: Pimpliness.
pin (n.): late Old English pinn "peg, bolt," from Proto-Germanic *penn- "jutting point or peak" (source also of Old Saxon pin "peg," Old Norse pinni "peg, tack," Middle Dutch pin "pin, peg," Old High German pfinn, German Pinne "pin, tack") from Latin pinna "a feather, plume;" in plural "a wing;" also "fin, scoop of a water wheel;" also "a pinnacle; a promontory, cape; battlement" (as in Luke iv:9 in Vulgate) and so applied to "points" of various sorts, from PIE *pet- (see pen (n.1)).

Latin pinna and penna "a feather, plume," in plural "a wing," are treated as identical in Watkins, etc., but regarded as separate (but confused) Latin words by Tucker and others, who derive pinna from PIE *spei- "sharp point" (see spike (n.1)) and see the "feather/wing" sense as secondary.

The modern slender wire pin is first attested by this name late 14c. Transferred sense of "leg" is recorded from 1520s and hold the older sense. Pin-money "annual sum allotted to a woman for personal expenses on dress, etc." is attested from 1620s. Pins and needles "tingling sensation" is from 1810. The sound of a pin dropping as a type of something all but silent is from 1775.
PIN: acronym for personal identification number, 1981, from the first reference used with redundant number.
pin (v.): mid-14c., "to affix with a pin," from pin (n.). Figurative use from 1570s. Related: Pinned; pinning. Sense of "to hold someone or something down so he or it cannot escape" is attested from 1740. In U.S., as a reference to the bestowal of a fraternity pin on a female student as an indication of a relationship, it is attested by 1938. Phrase pin down "define" is from 1951.
pin-ball (n.): as a type of game, 1907, from pin (n.) + ball (n.1). Originally of types of open-air bowling and basketball variation where the goal was to knock down a pin or pins. Earlier still it meant "pin-cushion." The tabletop pin-ball machine is attested from 1937.
pin-feather (n.): 1775, from pin (n.) + feather (n.).
pin-hole (n.): 1670s, from pin (n.) + hole (n.).
pin-stripe (adj.): 1882, from pin (n.) + stripe (n.). Figurative of "executive" by 1958.
pin-up (adj.): 1670s, from pin (v.) + up (adv.). From 1940, in reference to pictures of "winsome young ladies in daring undress" ("Life," May 6, 1940) such as soldiers pinned up on their dugout walls, etc. The thing itself is older than the name. The noun in this sense is recorded from 1943.