c. 1300 (early 13c. in surname Porkuiller), "flesh of a pig as food," from Old French porc "pig, swine, boar," and directly from Latin porcus "pig, tame swine," from PIE root *porko- "young pig." Also in Middle English "a swine, a hog" (c. 1400).
Pork barrel in the literal sense "barrel in which pork is kept" is from 1801, American English; the meaning "state's financial resources (available for distribution)" is attested from 1907 (in full, national pork barrel); it was noted as an expression of U.S. President President William Howard Taft:
"Now there is a proposition that we issue $500,000,000 or $1,000,000,000 of bonds for a waterway, and then that we just apportion part to the Mississippi and part to the Atlantic, a part to the Missouri and a part to the Ohio. I am opposed to it. I am opposed to it because it not only smells of the pork barrel, but it will be the pork barrel itself. Let every project stand on its bottom." [The Outlook, Nov. 6, 1909, quoting Taft]
The magazine article that includes the quote opens with:
We doubt whether any one knows how or when, or from what application of what story, the phrase "the National pork barrel" has come into use. If not a very elegant simile, it is at least an expressive one, and suggests a graphic picture of Congressmen eager for local advantage going, one after another, to the National pork barrel to take away their slices for home consumption.
Pork in this sense is attested from 1862 (compare figurative use of bacon). Pork chop "slice of meat from the ribs of a pork" is attested from 1858. Pork pie "pie made of pastry and minced pork" is from 1732; pork-pie hat (1855) originally described a woman's style popular c. 1855-65, but also worn by men. It was distinguished by a brim turned up around the low crown, a shape that resembled a deep pork pie.
1650s, "young hog fattened for food," from pork (n.). Meaning "fat person" is by 1892. Middle English had porknel "fat person" (c. 1400).
Proto-Indo-European root meaning "young pig."
It is the hypothetical source of/evidence for its existence is provided by: Latin porcus "pig, tame swine," Umbrian purka; Old Church Slavonic prase "young pig;" Lithuanian paršas "pig;" Middle Dutch varken, German Ferkel, Old English fearh "pig, small pig."
Middle English pigge "a young pig" (mid-13c., late 12c. as a surname), probably from Old English *picg, found in compounds, but, like dog, its further etymology unknown. The older general word for adults was swine, if female, sow, if male, boar. Apparently related to Low German bigge, Dutch big ("but the phonology is difficult" -- OED).
By early 14c. pig was used of a swine or hog regardless of age or sex. Applied to persons, usually in contempt, since 1540s; the derogatory meaning "police officer" has been in underworld slang at least since 1811.
The pigs frisked my panney, and nailed my screws; the officers searched my house, and seized my picklock keys. ["Dictionary of Buckish Slang, University Wit and Pickpocket Eloquence," London, 1811]
Another Old English word for the animal was fearh, which is related to furh "furrow," from PIE *perk- "dig, furrow" (source also of Latin porcus "pig," see pork). "This reflects a widespread IE tendency to name animals from typical attributes or activities" [Lass].
Synonyms grunter, porker are from sailors' and fishermen's euphemistic avoidance of uttering the word pig at sea, a superstition perhaps based on the fate of the Gadarene swine, who drowned. The image of a pig in a poke is attested from late 14c. (see poke (n.1)). Flying pigs as a type of something unreal is from 1610s.
"cold cuts of pork, sausage, etc.," 1858, from French charcuterie, literally "pork-butcher's shop," from charcutier "pork-butcher" (16c.), from obsolete char (Modern French chair) cuite "cooked flesh," from chair "meat" (Old French char, from Latin carnem "flesh," originally "a piece of flesh," from PIE root *sker- (1) "to cut") + cuit, past participle of cuire "to cook," from Latin coquere "to cook" (from PIE root *pekw- "to cook, ripen"). Compare French charcutier "pork butcher; meat roaster, seller of cooked (not raw) meat."
"spiced pork sausage," 1846, from Spanish chorizo, ultimately from Medieval Latin salsicia "sausage" from Latin salsicus "seasoned with salt" (see sausage).
"beef and pork sausage seasoned with pepper," by 1904, from Italian peperone "chilli," from pepe (see pepper (n.)).