"either of the two fleshy sides of the face below the eyes," Old English ceace, cece "jaw, jawbone," in late Old English also "the fleshy wall of the mouth," of uncertain origin, from Proto-Germanic *kaukon (source also of Middle Low German kake "jaw, jawbone," Middle Dutch kake "jaw," Dutch kaak), not found outside West Germanic, probably a substratum word.
Words for "cheek," "jaw," and "chin" tend to run together in IE languages (compare PIE *genw-, source of Greek genus "jaw, cheek," geneion "chin," and English chin); Aristotle considered the chin as the front of the "jaws" and the cheeks as the back of them. The other Old English word for "cheek" was ceafl (see jowl (n.1)).
A thousand men he [Samson] slow eek with his hond, And had no wepen but an asses cheek. [Chaucer, "Monk's Tale"]
In reference to the buttocks from c. 1600. Sense of "brazen insolence" is from 1840, perhaps from a notion akin to that which led to jaw "insolent speech," mouth off, etc. To turn the other cheek is an allusion to Matthew v.39 and Luke vi.29. Cheek-by-jowl "with cheeks close together," hence "in intimate contact" is from 1570s; earlier in same sense was cheek-by-cheek (early 14c.). In ballroom dancing, cheek-to-cheek is from 1919 (earlier it was a measurement of apples).
mid-12c., "large group of people," from Old French compagnie "society, friendship, intimacy; body of soldiers" (12c.), from Late Latin companio, literally "bread fellow, messmate," from Latin com "with, together" (see com-) + panis "bread," from PIE root *pa- "to feed." Abbreviation co. dates from 1670s.
Meaning "companionship, consort of persons one with another, intimate association" is from late 13c. Meaning "person or persons associated with another in any way" is from c. 1300. In Middle English the word also could mean "sexual union, intercourse" (c. 1300).
From late 14c. as "a number of persons united to perform or carry out anything jointly," which developed a commercial sense of "business association" by 1550s, the word having been used in reference to trade guilds from late 14c. Meaning "subdivision of an infantry regiment" (in 19c. usually 60 to 100 men, commanded by a captain) is from c. 1400.
Meaning "person or persons with whom one voluntarily associates" is from c. 1600; phrase keep company "consort" is from 1560s (bear company in the same sense is from c. 1300). Expression two's company "two persons are just right" (for conversation, etc.), is attested from 1849; the following line varies: but three is none (or not), 1849; three's trumpery (1864); three's a crowd (1856).
c. 1300, mariage, "action of entering into wedlock;" also "state or condition of being husband and wife, matrimony, wedlock;" also "a union of a man and woman for life by marriage, a particular matrimonial union;" from Old French mariage "marriage; dowry" (12c.), from Vulgar Latin *maritaticum (11c.), from Latin maritatus, past participle of maritare "to wed, marry, give in marriage" (see marry (v.)). The Vulgar Latin word also is the source of Italian maritaggio, Spanish maridaje, and compare mariachi.
Meanings "the marriage vow, formal declaration or contract by which two join in wedlock;" also "a wedding, the celebration of a marriage; the marriage ceremony" are from late 14c. Figurative use (non-theological) "intimate union, a joining as if by marriage" is from late 14c.
[W]hen two people are under the influence of the most violent, most insane, most delusive, and most transient of passions, they are required to swear that they will remain in that excited, abnormal, and exhausting condition until death do them part. [G.B. Shaw, preface to "Getting Married," 1908]
Marriage counseling is recorded by that name by 1939. Marriage bed, figurative of marital intercourse generally, is attested from 1580s (bed of marriage is from early 15c.).
"companion, comrade," c. 1200, from Old English feolaga "partner, one who shares with another," from Old Norse felagi, from fe "money" (see fee) + lag, from Proto-Germanic *lagam, from PIE root *legh- "to lie down, lay." The etymological sense of fellow seems to be "one who puts down money with another in a joint venture."
Meaning "one of the same kind" is from early 13c.; that of "one of a pair" is from c. 1300. Used familiarly since mid-15c. for "any man, male person," but not etymologically masculine (it is used of women, for example, in Judges xi.37 in the King James version: "And she said unto her father, Let this thing be done for me: let me alone two months, that I may go up and down upon the mountains, and bewail my virginity, I and my fellows").
Its use can be contemptuous or dignified in English and American English, and at different times in its history, depending on who used it to whom, it has carried a tinge of condescension or insult.
University senses (mid-15c., corresponding to Latin socius) evolved from notion of "one of the corporation who constitute a college" and who are paid from its revenues. Fellow well-met "boon companion" is from 1580s, hence hail-fellow-well-met as a figurative phrase for "on intimate terms."
In compounds, with a sense of "co-, joint-," from 16c., and by 19c. also denoting "association with another." Hence fellow-traveler, 1610s in a literal sense but in 20c. with a specific extended sense of "one who sympathizes with the Communist movement but is not a party member" (1936, translating Russian poputchik).
Fellow-countrymen formerly was one of the phrases the British held up to mock the Americans for their ignorance, as it is redundant to say both, until they discovered it dates from the 1580s and was used by Byron and others.