Online Etymology Dictionary

pop (n.2): "father," 1838, chiefly American English, shortened from papa (1680s), from French papa, from Old French, a children's word, similar to Latin pappa. Form poppa is recorded from 1897.
pop (v.): "cause to make a short, quick sound," mid-15c.; intransitive sense "make a short, quick sound" is from 1570s; imitative. Of eyes, "to protrude" (as if about to burst), from 1670s. Sense of "to appear or put suddenly" (often with up, off, in, etc.) is recorded from mid-15c. Baseball sense of "to hit a ball high in the air" is from 1867. To pop the question is from 1725, specific sense of "propose marriage" is from 1826. Related: Popped; popping.
pop-eyed (adj.): "having bulging eyes," 1820; see pop (v.) + eye (n.).
pop-gun (n.): type of child's toy, 1620s, from pop (n.1) + gun (n.).
pop-up (n.): from 1906 as a type of baseball hit; from pop (v.) + up (adv.). As an adjective from 1934 (of a children's book, later toasters, etc.).
popcorn (n.): 1819, from pop (v.) + corn (n.1).
pope (n.): Old English papa (9c.), from Church Latin papa "bishop, pope" (in classical Latin, "tutor"), from Greek papas "patriarch, bishop," originally "father." Applied to bishops of Asia Minor and taken as a title by the Bishop of Alexandria c.250. In Western Church, applied especially to the Bishop of Rome since the time of Leo the Great (440-461) and claimed exclusively by them from 1073 (usually in English with a capital P-). Popemobile, his car, is from 1979. Papal, papacy, later acquisitions in English, preserve the original vowel.
popery (n.): 1530s, a hostile coinage of the Reformation, from pope + -ery.
popinjay (n.): late 13c., "a parrot," from Old French papegai (12c.), from Spanish papagayo, from Arabic babagha', Persian babgha "parrot," possibly formed in an African or other non-Indo-European language and imitative of its cry. Ending probably assimilated in Western European languages to "jay" words (Old French jai, etc.).

Used of people in a complimentary sense (in allusion to beauty and rarity) from early 14c.; meaning "vain, talkative person" is first recorded 1520s. Obsolete figurative sense of "a target to shoot at" is explained by Cotgrave's 2nd sense definition: "also a woodden parrot (set up on the top of a steeple, high tree, or pole) whereat there is, in many parts of France, a generall shooting once euerie yeare; and an exemption, for all that yeare, from La Taille, obtained by him that strikes downe" all or part of the bird.
popish (adj.): 1520s, from pope + -ish.
poplar (n.): mid-14c., from Anglo-French popler, from Old French poplier (13c., Modern French peulplier), from Latin populus "poplar" (with a long "o;" not the same word that produced popular), of unknown origin, possibly from a PIE tree-name root *p(y)el- (cf. Greek pelea "elm"). Italian pioppo, Spanish chopo, German pappel, Old Church Slavonic topoli all are from Latin.
poplin (n.): type of corded fabric, 1710, from French papeline "cloth of fine silk and worsted" (1660s), probably from Provençal papalino, fem. of papalin "of or belonging to the pope," from Medieval Latin papalis "papal" (see papal). The reference is to Avignon, papal residence during the schism 1309-1408 (and regarded as a papal town until 1791), which also was a center of silk manufacture. Influenced in English by Poperinghe, town in Flanders where the fabric was made (but from 18c. the primary source was Ireland).
popliteal (adj.): 1786, with -al (1) + Modern Latin popliteus (n.), 1704, short for popliteus (musculus), from poples "ham (of the leg)," which is of unknown origin.
popover (n.): also pop-over, "light cake," 1859, from pop (v.) + over (adv.).
poppet (n.): "small human figure used in witchcraft and sorcery," c.1300, early form of puppet (n.). Meaning "small or dainty person" is recorded from late 14c.; later a term of endearment but also in other cases one of contempt.
poppy (n.): late Old English popig, popæg, from West Germanic *papua-, probably from Vulgar Latin *papavum, from Latin papaver "poppy," perhaps a reduplicated form of imitative root *pap- "to swell." Associated with battlefields and war dead at least since Waterloo (1815). Poppy-seed is from early 15c.; in 17c. it also was a small unit of length (less than one-twelfth of an inch).
poppycock (n.): 1865, American English, probably from Dutch dialect pappekak, from Middle Dutch pappe "soft food" (see pap) + kak "dung," from Latin cacare "to excrete" (see caca).
popsicle (n.): 1923, trademark name registered by Frank Epperson of Oakland, Calif., presumably from (lolly)pop + (ic)icle.
popster (n.): pop-culture enthusiast, 1963, from pop (adj.)+ -ster.
populace (n.): 1570s, from Middle French populace (16c.), from Italian popolaccio "riffraff, rabble," from popolo "people" (from Latin populus "people;" see people (n.)) + pejorative suffix -accio.
popular (adj.): early 15c., "public," from Middle French populier (Modern French populaire) and directly from Latin popularis "belonging to the people, general, common; devoted to or accepted by the people; democratic," from populus "people" (see people (n.)).

Meaning "suited to ordinary people" is from 1570s in English; hence, of prices, "low, affordable to average persons" (1859). Meaning "well-liked, admired by the people" is attested from c.1600. Of art, entertainment, etc., "favored by people generally" from 1819 (popular song). Related: Popularly. Popular Front "coalition of Communists, Socialists, and radicals" is from 1936, first in a French context.
popularity (n.): "fact or condition of being beloved by the people," c.1600, from French popularité (15c.), from popular + -ity. Classical Latin popularitas meant "fellow-citizenship." Popularity contest is from 1880.
popularization (n.): 1797, noun of action from popularize.
popularize (v.): "to make a complex topic intelligible to the people," 1833, from popular + -ize. Earlier "to cater to popular taste" (1590s); "to make popular" (1797). Related: Popularized; popularizing.
populate (v.): 1610s, from Medieval Latin populatus, past participle of populare "inhabit, to people," from Latin populus "inhabitants, people, nation" (see people (n.)). Related: Populated; populating.
population (n.): 1610s, from Late Latin populationem (nominative populatio) "a people; a multitude," as if from Latin populus "a people" (see people (n.)). Population explosion is first attested 1953.
populism (n.): 1893; see populist + -ism. Originally in reference to the political theories of the U.S. Populist Party (also People's Party).
populist: 1892 (n.) "adherent of populism;" 1893 (adj.), American English, from Latin populus "people" (see people (n.)) + -ist. Originally in reference to the U.S. Populist Party organized February 1892 to promote certain issues important to farmers and workers. The term outlasted the party, and by 1920s came to mean "representing the views of the masses" in a general way.
populous (adj.): early 15c., from post-classical Latin populosus "full of people, populous," from populus "people" (see people (n.)). Related: Populousness.
porcelain (n.): 1530s, from Middle French porcelaine and directly from Italian porcellana "porcelain" (13c.), literally "cowrie shell," the chinaware so called from resemblance of its lustrous transparency to the shiny surface of the shells. The shell's name in Italian is from porcella "young sow," fem. of Latin porcellus "young pig," diminutive of porculus "piglet," diminutive of porcus "pig" (see pork (n.)). According to an old theory, the connection of the shell and the pig is a perceived resemblance of the shell opening to the exposed outer genitalia of pigs.
porcelain is china & china is p.; there is no recondite difference between the two things, which indeed are not two, but one; & the difference between the two words is merely that china is the homely term, while porcelain is exotic & literary. [Fowler]
porch (n.): c.1300, "covered entrance," from Old French porche "porch, vestibule," from Latin porticus "covered gallery, covered walk between columns, arcade, portico, porch," from porta "gate, entrance, door" (see port (n.2)). The Latin word was borrowed directly into Old English as portic.
porcine (adj.): early 15c., "pertaining to swine; swinish," from Old French porcin or directly from Latin porcinus "of a hog," from porcus "hog, pig" (see pork (n.)).
porcupine (n.): c.1400, porke despyne, from Old French porc-espin (early 13c., Modern French porc-épic), literally "spiny pig," from Latin porcus "hog" + spina "thorn, spine" (see spike (n.1)). The word had many forms in Middle English and early Modern English, including portepyn, porkpen, porkenpick, porpoynt, and Shakespeare's porpentine (in "Hamlet").
pore (v.): "gaze intently," early 13c., of unknown origin, with no obvious corresponding word in Old French. Perhaps from Old English *purian, suggested by spyrian "to investigate, examine," and spor "a trace, vestige." Related: Pored; poring.
pore (n.): "minute opening," late 14c., from Old French pore (14c.) and directly from Latin porus "a pore," from Greek poros "a pore," literally "passage, way," from PIE *por- "going, passage," from root *per- "to lead, pass over" (see port (n.1)).
porgy (n.): name given to various sea fishes, 1725, probably from pargo "sea bream" (1550s), from Spanish or Portuguese pargo, from Latin phagrum (nom. phager), from Greek phagros "sea bream."
Porifera (n.): 1843, Modern Latin, literally "bearing pores," neuter plural of porifer, from Latin porus "pore, opening" (see pore (n.)) + -fer "bearing" (see infer). Related: Poriferal; poriferous.
pork (n.): 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 *porko- "young swine" (cf. Umbrian purka; Old Church Slavonic prase "young pig;" Lithuanian parsas "pig;" and Old English fearh, Middle Dutch varken, both from Proto-Germanic *farhaz).

Pork barrel in the literal sense is from 1801, American English; 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 (cf. figurative use of bacon). Pork chop is attested from 1858. Pork pie is from 1732; pork-pie hat (1855) originally described a woman's style popular c.1855-65, so called for its shape.
porker (n.): 1650s, "young hog fattened for food," from pork (n.). Meaning "fat person" is from 1892.
porky (adj.): 1852, from pork (n.) + -y (2). Related: Porkiness.
porn (n.): 1962, abbreviation of pornography. Porno (adj.) is attested from 1952.
porno (adj.): 1952 (Norman Mailer), short for pornographic.
pornographer (n.): 1850, from pornography + -er (1).
pornographic (adj.): 1853, from pornography + -ic.
pornography (n.): 1843, "ancient obscene painting, especially in temples of Bacchus," from French pornographie, from Greek pornographos "(one) depicting prostitutes," from porne "prostitute," originally "bought, purchased" (with an original notion, probably of "female slave sold for prostitution"), related to pernanai "to sell," from PIE root *per- (5) "to traffic in, to sell" (see price (n.)) + graphein "to write" (see -graphy). A brothel in ancient Greek was a porneion.

In reference to modern works by 1859 (originally French novels), later as a charge against native literature; sense of "obscene pictures" in modern times is from 1906. Also sometimes used late 19c. for "description of prostitutes" as a matter of public hygiene. The "Medical Archives" in 1873 proposed porniatria for "the lengthy and really meaningless expression 'social evil hospital' ...."
I shall not today attempt further to define the kinds of material I understand to be embraced within that shorthand description [hard-core pornography]; and perhaps I could never succeed in intelligibly doing so. But I know it when I see it, and the motion picture involved in this case is not that. [U.S. Supreme Court Justice Potter Stewart, concurring opinion, "Jacobellis v. Ohio," 1964]
In ancient contexts, often paired with rhypography, "genre painting of low, sordid, or unsuitable subjects." Pornocracy (1860) is "the dominating influence of harlots," used specifically of the government of Rome during the first half of the 10th century by Theodora and her daughters. Pornotopia (1966) was coined to describe the ideal erotic-world of pornographic movies.
porosity (n.): late 14c., from Old French porosité, from Medieval Latin porositas, from porus (see pore (n.)).
porous (adj.): late 14c., "full of pores," from Old French poros (14c., Modern French poreux), from Medieval Latin porosus; or directly from Latin porus "an opening" (see pore (n.)). Figurative use from 1640s.
porphyria (n.): metabolic disorder, 1923, from porphyrin (1910), the ame of the type of chemical which, in imbalance, causes it, from German porphyrin, chemical name, from Greek porphyros "purple" (see purple) + -in (2). Some of the compounds are purple.
porphyrite (n.): 1796 as a modern mineral name, from porphyry + -ite (2). Related: Porphyritic.
porphyry (n.): type of ornamental stone, late 14c., porfurie, from Old French porfire, from Italian porfiro and in some cases directly from Latin porphyrites, a purple semi-precious stone quarried near the Red Sea in Egypt, from Greek porphyrites (lithos) "the purple (stone)," from porphyra (n.) "purple, purple dye" (see purple). Spelling Latinized mid-15c. Now used generally for a type of igneous rock without regard to color. Porphyrios was an ancient proper name.