"close growth of hair on the chin and lower face, normally characteristic of an adult male" (that of the upper lip being distinguished in Modern English as the mustache), Old English beard "beard," from Proto-Germanic *bard (source also of Old Frisian berd, Middle Dutch baert, Old High German bart, German bart), said in Pokorny to be from a PIE root *bhardhā- "beard" (source also of Old Church Slavonic brada, Russia boroda, Lithuanian barzda, Old Prussian bordus, and perhaps Latin barba "beard"), but Boutkan rejects this on phonetic grounds and suggests a non-IE substrate word. Old French berd is from Germanic.
The Greek and Roman Churches have long disputed about the beard. While the Romanists have at different times practised shaving, the Greeks, on the contrary, have strenuously defended the cause of long beards. Leo III. (795 AD) was the first shaved Pope. Pope Gregory IV., after the lapse of only 30 years, fulminated a Bull against bearded priests. In the 12th century the prescription of the beard was extended to the laity. Pope Honorius III. to disguise his disfigured lip, allowed his beard to grow. Henry I. of England was so much moved by a sermon directed against his beard that he resigned it to the barber. Frederick Barbarossa is said to have been equally tractable. [Tom Robinson, M.D., "Beards," St. James's Magazine, 1881]
Pubic hair sense is from 1600s (but neþir berd "pubic hair" is from late 14c.); in the 1811 "Dictionary of the Vulgar Tongue," the phrase beard-splitter is defined as, "A man much given to wenching" (compare beaver in the slang genital sense).
in the sports sense, 1879, originally in cricket, "taking three wickets on three consecutive deliveries;" extended to other sports c. 1909, especially ice hockey ("In an earlier contest we had handed Army a 6-2 defeat at West Point as Billy Sloane performed hockey's spectacular 'hat trick' by scoring three goals" ["Princeton Alumni Weekly," Feb. 10, 1941]). So called allegedly because it entitled the bowler to receive a hat from his club commemorating the feat (or entitled him to pass the hat for a cash collection), but the term probably has been influenced by the image of a conjurer pulling objects from his hat (an act attested by 1876). The term was used earlier for a different sort of magic trick:
Place a glass of liquor on the table, put a hat over it, and say, "I will engage to drink every drop of that liquor, and yet I'll not touch the hat." You then get under the table; and after giving three knocks, you make a noise with your mouth, as if you were swallowing the liquor. Then, getting from under the table, say "Now, gentlemen, be pleased to look." Some one, eager to see if you have drunk the liquor, will raise the hat; when you instantly take the glass and swallow the contents, saying, "Gentlemen I have fulfilled my promise: you are all witnesses that I did not touch the hat." ["Wit and Wisdom," London, 1860]
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.
mid-13c., boie "servant, commoner, knave" (generally young and male); c. 1300, "rascal, ruffian, knave; urchin," mid-14c. as "male child before puberty" (possibly an extended sense from the "urchin" one). A word of unknown origin.
Possibly from Old French embuie "one fettered," from Vulgar Latin *imboiare, from Latin boia "leg iron, yoke, leather collar," from Greek boeiai dorai "ox hides." (Words for "boy" double as "servant, attendant" across the Indo-European map -- compare Italian ragazzo, French garçon, Greek pais, Middle English knave, Old Church Slavonic otroku -- and often it is difficult to say which meaning came first.)
But it also appears to be identical with East Frisian boi "young gentleman," and perhaps with Dutch boef "knave," from Middle Dutch boeve, perhaps from Middle Low German buobe. This suggests a gradational relationship to babe. For a different conjecture: Used slightingly of young men in Middle English, also in familiar or contemptuous use of criminal toughs or men in the armed services. In some local uses "a man," without reference to age (OED lists "in Cornwall, in Ireland, in the far West of the U.S."). Meaning "male negro slave or Asian personal servant of any age" attested from c. 1600. Extended form boyo is attested from 1870. Emphatic exclamation oh, boy is attested by 1917. Boy-meets-girl "typical of a conventional romance" is from 1945; the phrase itself is from 1934 as a dramatic formula. Boy-crazy "eager to associate with males" is from 1923.
In Old English, only the proper name Boia has been recorded. ME boi meant 'churl, servant' and (rarely) 'devil.' In texts, the meaning 'male child' does not antedate 1400. ModE boy looks like a semantic blend of an onomatopoeic word for an evil spirit (*boi) and a baby word for 'brother' (*bo). [Liberman]
A noticable number of the modern words for 'boy', 'girl', and 'child' were originally colloquial nicknames, derogatory or whimsical, in part endearing, and finally commonplace. These, as is natural, are of the most diverse, and in part obscure, origin. [Buck]