Middle English sēn, from Old English seon (Anglian sean) "be or become aware of by means of the eye; look, behold;" also "perceive mentally, understand; experience; visit (a place); inspect" (contracted class V strong verb; past tense seah, past participle sewen), from Proto-Germanic *sehwanan (source also of Old Saxon, Old High German sehan, Middle High German, German sehen, Old Frisian sia, Middle Dutch sien, Old Norse sja, Gothic saihwan).
This is reconstructed to be from PIE root *sekw- (2) "to see." That PIE root often was said to be probably identical with *sekw- (1) "to follow," which produced words for "say" in Greek and Latin, and also words for "follow" (such as Latin sequor), but "opinions differ in regard to the semantic starting-point and sequences" [Buck]. Thus see might mean, etymologically, "follow with the eyes" (and in some languages extending to "speak, say, tell"). But OED finds this "involves a hypothetical sense-development which it is not easy to accept with confidence," and Boutkan also doubts the connection and gives the word "No certain PIE etymology."
It is attested by late Old English as "be able to see with the eyes, have the faculty of sight, not be blind."
As the sense of sight affords far more complete and definite information respecting external objects than any other of the senses, mental perceptions are in many (perh. in all) languages referred to in visual terms, and often with little or no consciousness of metaphor. [OED]
English see has been used in many of these senses since early Middle English: "foresee; behold in the imagination or in a dream," also "to recognize the force of (a demonstration)," all c. 1200.
It is attested by c. 1300 as "ensure, make sure" (something is so, someone does something). To see to is by late 14c. as "be attentive to, take special care about" (also "to look at"); hence "attend to, arrange for, bring about as a result." See to it "take special care; see that it be done" is from late 15c.
The sense of "escort" (as in see you home) is attested c. 1600 in Shakespeare. The meaning "to receive as a visitor" is attested from c. 1500. The wagering sense of "equal a bet, accept by staking a similar sum" is by 1590s. Used in phrases expressing comparative and superlative (best I've ever seen) from early 14c.
Imperative use of see! "look! behold!" is by early 14c. Emphatic expression see here is attested from early 15c.; probably the notion is "see, here is ...;" but the modern use of it as "a brusque form of address used to preface an order," etc. [OED] is by 1897 in schoolboy talk. The qualifying expression as far as I can see is attested from 1560s.
Let me see as a statement expressing consideration when the speaker is trying to recall something is recorded from 1510s. See you as a casual farewell is attested by 1891 (see you soon; probably short for hope to see you soon). To see something in (someone, etc.) "perceive good or attractive qualities in" is by 1832.
c. 1200, from Old Norse geta (past tense gatum, past participle getenn) "to obtain, reach; to be able to; to beget; to learn; to be pleased with," a word of very broad meaning, often used almost as an auxilliary verb, also frequently in phrases (such as geta rett "to guess right"). This is from Proto-Germanic *getan (source also of Old Swedish gissa "to guess," literally "to try to get"), from PIE root *ghend- "to seize, take."
Old English, as well as Dutch and Frisian, had the verb almost exclusively in compounds (such as begietan, "to beget;" forgietan "to forget"). Vestiges of an Old English cognate *gietan remain obliquely in modern past participle gotten and original past tense gat, also Biblical begat.
In compound phrases with have and had it is grammatically redundant, but often usefully indicates possession, obligation, or necessity, or gives emphasis. The word and phrases built on it take up 29 columns in the OED 2nd edition; Century Dictionary lists seven distinct senses for to get up.
"I GOT on Horseback within ten Minutes after I received your Letter. When I GOT to Canterbury I GOT a Chaise for Town. But I GOT wet through before I GOT to Canterbury, and I HAVE GOT such a Cold as I shall not be able to GET rid of in a Hurry. I GOT to the Treasury about Noon, but first of all I GOT shaved and drest. I soon GOT into the Secret of GETTING a Memorial before the Board, but I could not GET an Answer then, however I GOT Intelligence from the Messenger that I should most likely GET one the next Morning. As soon as I GOT back to my Inn, I GOT my Supper, and GOT to Bed, it was not long before I GOT to Sleep. When I GOT up in the Morning, I GOT my Breakfast, and then GOT myself drest, that I might GET out in Time to GET an Answer to my Memorial. As soon as I GOT it, I GOT into the Chaise, and GOT to Canterbury by three: and about Tea Time, I GOT Home. I HAVE GOT No thing particular for you, and so Adieu." [Philip Withers, "Aristarchus, or the Principles of Composition," London, 1789, illustrating the widespread use of the verb in Modern English]
As a command to "go, be off" by 1864, American English. Meaning "to seize mentally, grasp" is from 1892. Get wind of "become acquainted with" is from 1840, from earlier to get wind "to get out, become known" (1722). To get drunk is from 1660s; to get religion is from 1772; to get better "recover health" is from 1776. To get ready "prepare oneself" is from 1890; to get going "begin, start doing something" is by 1869 in American English; get busy "go into action, begin operation" is from 1904. Get lost as a command to go away is by 1947. To get ahead "make progress" is from 1807. To get to (someone) "vex, fret, obsess" is by 1961, American English (get alone as "to puzzle, trouble, annoy" is by 1867, American English). To get out of hand originally (1765) meant "to advance beyond the need for guidance;" sense of "to break free, run wild" is from 1892, from horsemanship. To get on (someone's) nerves is attested by 1970.
"a featherless plantigrade biped mammal of the genus Homo" [Century Dictionary], Old English man, mann "human being, person (male or female); brave man, hero;" also "servant, vassal, adult male considered as under the control of another person," from Proto-Germanic *mann- (source also of Old Saxon, Swedish, Dutch, Old High German man, Old Frisian mon, German Mann, Old Norse maðr, Danish mand, Gothic manna "man"), from PIE root *man- (1) "man." For the plural, see men.
Sometimes connected to root *men- (1) "to think," which would make the ground sense of man "one who has intelligence," but not all linguists accept this. Liberman, for instance, writes, "Most probably man 'human being' is a secularized divine name" from Mannus [Tacitus, "Germania," chap. 2], "believed to be the progenitor of the human race."
Specific sense of "adult male of the human race" (distinguished from a woman or boy) is by late Old English (c. 1000); Old English used wer and wif to distinguish the sexes, but wer began to disappear late 13c. and was replaced by man. Universal sense of the word remains in mankind and manslaughter. Similarly, Latin had homo "human being" and vir "adult male human being," but they merged in Vulgar Latin, with homo extended to both senses. A like evolution took place in Slavic languages, and in some of them the word has narrowed to mean "husband." PIE had two other "man" roots: *uiHro "freeman" (source of Sanskrit vira-, Lithuanian vyras, Latin vir, Old Irish fer, Gothic wair; see *wi-ro-) and *hner "man," a title more of honor than *uiHro (source of Sanskrit nar-, Armenian ayr, Welsh ner, Greek anēr; see *ner- (2)).
Man also was in Old English as an indefinite pronoun, "one, people, they." It was used generically for "the human race, mankind" by c. 1200. As a word of familiar address, originally often implying impatience, c.1400; hence probably its use as an interjection of surprise or emphasis, since Middle English but especially popular from early 20c.
As "a woman's lover," by mid-14c. As "adult male possessing manly qualities in an eminent degree," from 14c. Man's man, one whose qualities are appreciated by other men, is by 1873. Colloquial use of the Man for "the boss" is by 1918. To be man or mouse "be brave or be timid" is from 1540s. Meaning "piece with which a game (especially chess) is played" is from c. 1400.
Man-about-town "man of the leisure class who frequents clubs, theaters, and other social resorts" is from 1734. Man of the world is from mid-14c. as "secular man, layman;" by early 15c. as "man experienced in the ways of the world, one able to take things in stride." To do something as one man "unanimously" is from late 14c.
So I am as he that seythe, 'Come hyddr John, my man.' 
MANTRAP, a woman's commodity. [Grose, "Dictionary of the Vulgar Tongue," London, 1785]
At the kinges court, my brother, Ech man for himself. [Chaucer, "Knight's Tale," c. 1386]
Old English, "move swiftly by using the legs, go on legs more rapidly than walking," also "make haste, hurry; be active, pursue or follow a course," and, of inanimate things, "to move over a course."
The modern verb is a merger of two related Old English words, in both of which the initial two letters sometimes switched places. The first is intransitive rinnan, irnan "to run, flow, run together" (past tense ran, past participle runnen), which is cognate with Middle Dutch runnen, Old Saxon, Old High German, Gothic rinnan, German rinnen "to flow, run."
The second is Old English transitive weak verb ærnan, earnan "ride, run to, reach, gain by running" (probably a metathesis of *rennan), from Proto-Germanic *rannjanan, causative of the root *ren- "to run." This is cognate with Old Saxon renian, Old High German rennen, German rennen, Gothic rannjan.
Watkins says both are from PIE *ri-ne-a-, nasalized form of root *rei- "to run, flow," but Boutkan's sources find this derivation doubtful based on the poor attestation of supposed related forms, and he lists it as of "No certain IE etymology."
Of streams, etc., "to flow," from late Old English. From c. 1200 as "take flight, retreat hurriedly or secretly." Phrase run for it "take flight" is attested from 1640s.
Also from c. 1200 as "compete in a race." Extended to "strive for any ends," especially "enter a contest for office or honors, stand as a candidate in an election" (1826, American English).
Of any sort of hurried travel, c. 1300. From early 13c. as "have a certain direction or course." By c. 1300 as "keep going, extend through a period of time, remain in existence." Specifically of theater plays by 1808. Of conveyances, stage lines, etc., "perform a regular passage from place to place" by 1817.
Of machinery or mechanical devices, "go through normal or allotted movements or operation," 1560s. Of colors, "to spread in a fabric when exposed to moisture," 1771. Of movie film, "pass between spools," hence "be shown," by 1931.
The meaning "carry on" (a business, etc.) is by 1861, American English; hence extended senses of "look after, manage." As "publish or print in a newspaper or magazine," by 1884.
Many senses are via the notion of "pass into or out of a certain state." To run dry "cease to yield water or milk" (1630s). In commerce, "be of a specified price, size, etc.," by 1762. To run low "be nearly exhausted" is by 1712; to run short "exhaust one's supply" is from 1752; to run out of in the same sense is from 1713. To run on "keep on, continue without pause or change" is from 1590s.
The transitive sense of "cause to run" was in Old English. By late 15c. as "to pierce, stab," hence 1520s as "thrust through or into something." The meaning "enter (a horse) in a race" is from 1750. The sense of "cause a mechanical device to keep moving or working" is by 1817.
Many figurative uses are from horseracing or hunting (such as to run (something) into the ground "carry to excess, exhaust by constant pursuit," 1836, American English).
To run across "meet by chance, fall in with" is attested from 1855, American English. To run into in this sense is by 1902. To run around with "consort with" is from 1887.
In reference to fevers by 1918. To run a (red) traffic signal is by 1933. Of tests, experiments, etc., by 1947. Of computers by 1952. Time has been running out since c. 1300. To run in the family is by 1771. The figurative expression run interference (1929) is from U.S. football. To run late is from 1954.
1937, coined in the fantasy tales of J.R.R. Tolkien (1892-1973).
On a blank leaf I scrawled: 'In a hole in the ground there lived a hobbit.' I did not and do not know why. [Tolkien, letter to W.H. Auden, dated 1955]
The word also turns up in a very long list of folkloric supernatural creatures in the writings of Michael Aislabie Denham (d. 1859) as an aside to his explanation that those born on Christmas Eve cannot see spirits. Denham was an early folklorist who concentrated on Northumberland, Durham, Westmoreland, Cumberland, the Isle of Man, and Scotland. This was printed in volume 2 of "The Denham Tracts" [ed. James Hardy, London: Folklore Society, 1895], a compilation of Denham's scattered publications.
What a happiness this must have been seventy or eighty years ago and upwards, to those chosen few who had the good luck to be born on the eve of this festival of all festivals; when the whole earth was so overrun with ghosts, boggles, bloody-bones, spirits, demons, ignis fatui, brownies, bugbears, black dogs, specters, shellycoats, scarecrows, witches, wizards, barguests, Robin-Goodfellows, hags, night-bats, scrags, breaknecks, fantasms, hobgoblins, hobhoulards, boggy-boes, dobbies, hob-thrusts, fetches, kelpies, warlocks, mock-beggars, mum-pokers, Jemmy-burties, urchins, satyrs, pans, fauns, sirens, tritons, centaurs, calcars, nymphs, imps, incubuses, spoorns, men-in-the-oak, hell-wains, fire-drakes, kit-a-can-sticks, Tom-tumblers, melch-dicks, larrs, kitty-witches, hobby-lanthorns, Dick-a-Tuesdays, Elf-fires, Gyl-burnt-tales, knockers, elves, rawheads, Meg-with-the-wads, old-shocks, ouphs, pad-foots, pixies, pictrees, giants, dwarfs, Tom-pokers, tutgots, snapdragons, sprets, spunks, conjurers, thurses, spurns, tantarrabobs, swaithes, tints, tod-lowries, Jack-in-the-Wads, mormos, changelings, redcaps, yeth-hounds, colt-pixies, Tom-thumbs, black-bugs, boggarts, scar-bugs, shag-foals, hodge-pochers, hob-thrushes, bugs, bull-beggars, bygorns, bolls, caddies, bomen, brags, wraiths, waffs, flay-boggarts, fiends, gallytrots, imps, gytrashes, patches, hob-and-lanthorns, gringes, boguests, bonelesses, Peg-powlers, pucks, fays, kidnappers, gallybeggars, hudskins, nickers, madcaps, trolls, robinets, friars' lanthorns, silkies, cauld-lads, death-hearses, goblins, hob-headlesses, bugaboos, kows, or cowes, nickies, nacks necks, waiths, miffies, buckies, ghouls, sylphs, guests, swarths, freiths, freits, gy-carlins Gyre-carling, pigmies, chittifaces, nixies, Jinny-burnt-tails, dudmen, hell-hounds, dopple-gangers, boggleboes, bogies, redmen, portunes, grants, hobbits, hobgoblins, brown-men, cowies, dunnies, wirrikows, alholdes, mannikins, follets, korreds, lubberkins, cluricauns, kobolds, leprechauns, kors, mares, korreds, puckles korigans, sylvans, succubuses, blackmen, shadows, banshees, lian-hanshees, clabbernappers, Gabriel-hounds, mawkins, doubles, corpse lights or candles, scrats, mahounds, trows, gnomes, sprites, fates, fiends, sibyls, nicknevins, whitewomen, fairies, thrummy-caps, cutties, and nisses, and apparitions of every shape, make, form, fashion, kind and description, that there was not a village in England that had not its own peculiar ghost. Nay, every lone tenement, castle, or mansion-house, which could boast of any antiquity had its bogle, its specter, or its knocker. The churches, churchyards, and crossroads were all haunted. Every green lane had its boulder-stone on which an apparition kept watch at night. Every common had its circle of fairies belonging to it. And there was scarcely a shepherd to be met with who had not seen a spirit!
[Emphasis added] It is curious that the name occurs nowhere else in folklore, and there is no evidence that Tolkien ever saw this. The word also was recorded from 1835 as "a term generally used in Wales to express a quantity made up of four Welsh pecks" [in English court records for Hughes vs. Humphreys, a weights-and-measures case from Wales]. Hobbitry attested from 1947.
late 14c., "full of joy, merry; light-hearted, carefree;" also "wanton, lewd, lascivious" (late 12c. as a surname, Philippus de Gay), from Old French gai "joyful, happy; pleasant, agreeably charming; forward, pert; light-colored" (12c.; compare Old Spanish gayo, Portuguese gaio, Italian gajo, probably French loan-words). Ultimate origin disputed; perhaps from Frankish *gahi (related to Old High German wahi "pretty"), though not all etymologists accept this.
Meaning "stately and beautiful; splendid and showily dressed" is from early 14c. Of things, "sumptuous, showy, rich, ornate," mid-14c. of colors, etc., "shining, glittering, gleaming, bright, vivid," late 14c.; of persons, "dressed up, decked out in finery," late 14c.
In the English of Yorkshire and Scotland formerly it could mean "moderately, rather, considerable" (1796; compare sense development in pretty (adj.)).
The word gay by the 1890s had an overall tinge of promiscuity -- a gay house was a brothel. The suggestion of immorality in the word can be traced back at least to the 1630s, if not to Chaucer:
But in oure bed he was so fressh and gay
Whan that he wolde han my bele chose.
Slang meaning "homosexual" (adj.) begins to appear in psychological writing late 1940s, evidently picked up from gay slang and not always easily distinguished from the older sense:
After discharge A.Z. lived for some time at home. He was not happy at the farm and went to a Western city where he associated with a homosexual crowd, being "gay," and wearing female clothes and makeup. He always wished others would make advances to him. [Rorschach Research Exchange and Journal of Projective Techniques, 1947, p.240]
The association with (male) homosexuality likely got a boost from the term gay cat, used as far back as 1893 in American English for "young hobo," one who is new on the road, also one who sometimes does jobs.
"A Gay Cat," said he, "is a loafing laborer, who works maybe a week, gets his wages and vagabonds about hunting for another 'pick and shovel' job. Do you want to know where they got their monica (nickname) 'Gay Cat'? See, Kid, cats sneak about and scratch immediately after chumming with you and then get gay (fresh). That's why we call them 'Gay Cats'." [Leon Ray Livingston ("America's Most Celebrated Tramp"), "Life and Adventures of A-no. 1," 1910]
Quoting a tramp named Frenchy, who might not have known the origin. Gay cats were severely and cruelly abused by "real" tramps and bums, who considered them "an inferior order of beings who begs of and otherwise preys upon the bum -- as it were a jackal following up the king of beasts" [Prof. John J. McCook, "Tramps," in "The Public Treatment of Pauperism," 1893], but some accounts report certain older tramps would dominate a gay cat and employ him as a sort of slave. In "Sociology and Social Research" (1932-33) a paragraph on the "gay cat" phenomenon notes, "Homosexual practices are more common than rare in this group," and gey cat "homosexual boy" is attested in Noel Erskine's 1933 dictionary of "Underworld & Prison Slang" (gey is a Scottish variant of gay).
The "Dictionary of American Slang" reports that gay (adj.) was used by homosexuals, among themselves, in this sense at least since 1920. Rawson ["Wicked Words"] notes a male prostitute using gay in reference to male homosexuals (but also to female prostitutes) in London's notorious Cleveland Street Scandal of 1889. Ayto ["20th Century Words"] calls attention to the ambiguous use of the word in the 1868 song "The Gay Young Clerk in the Dry Goods Store," by U.S. female impersonator Will S. Hays, but the word evidently was not popularly felt in this sense by wider society until the 1950s at the earliest.
"Gay" (or "gai") is now widely used in French, Dutch, Danish, Japanese, Swedish, and Catalan with the same sense as the English. It is coming into use in Germany and among the English-speaking upper classes of many cosmopolitan areas in other countries. [John Boswell, "Christianity, Social Tolerance, and Homosexuality," 1980]
As a teen slang word meaning "bad, inferior, undesirable," without reference to sexuality, from 2000.