late 14c., from French galaxie or directly from Late Latin galaxias "the Milky Way" as a feature in the night sky (in classical Latin via lactea or circulus lacteus), from Greek galaxias (adj.), in galaxias kyklos, literally "milky circle," from gala (genitive galaktos) "milk" (from PIE root *g(a)lag- "milk").
The technical astronomical sense in reference to the discrete stellar aggregate including the sun and all visible stars emerged by 1848. Figurative sense of "brilliant assembly of persons" is from 1580s. Milky Way is a translation of Latin via lactea.
See yonder, lo, the Galaxyë Which men clepeth the Milky Wey, For hit is whyt. [Chaucer, "House of Fame"]
Originally ours was the only one known. Astronomers began to speculate by mid-19c. that some of the spiral nebulae they could see in telescopes were actually immense and immensely distant structures the size and shape of the Milky Way. But the matter was not settled in the affirmative until the 1920s.
As an affirmative meaning "yes, certainly" it dates from 1803, from Middle English meanings "firmly established; having no doubt," and phrases like to be sure (1650s), sure enough (1540s), and for sure (1580s). The use as an adverb meaning "assuredly" goes back to early 14c. Sure-footed is from 1630s, literal and figurative; sure thing dates from 1836. In 16c.-17c., Suresby was an appellation for a person to be depended upon (see rudesby).
"one, a or an, some," Old English ænig (adjective, pronoun) "any, anyone," literally "one-y," from Proto-Germanic *ainagas (source also of Old Saxon enig, Old Norse einigr, Old Frisian enich, Dutch enig, German einig), from PIE root *oi-no- "one, unique." The -y may have diminutive force here.
As a noun, late 12c.; as an adverb, "in any degree," c. 1400. Emphatic form any old______ (British variant: any bloody ______) is recorded from 1896. At any rate is recorded from 1847. Among the large family of compounds beginning with any-, anykyn "any kind" (c. 1300) did not survive, and Anywhen (1831) is rarely used, but OED calls it "common in Southern [English] dialects."
[A]ani refers to single entities, amounts, etc., occurring at random or chosen at random, as being convenient, suitable, to one's liking, etc. It is frequently emphatic and generalizing, having the force of 'any whatever, any at all' and 'any and every'. It is common in questions, conditional clauses, and negative statements, but not in affirmative statements (where som is used instead). [The Middle English Compendium]
Meaning "discharge of blood or other fluid from the body" is from 1520s; sense of "offspring, children" is from late 14c. Meaning "outcome of an action, consequence, result" is attested from late 14c., probably from this sense in French. Meaning "action of sending into publication or circulation" is from 1833.
Legal sense developed from the notion of "end or result of pleadings in a suit (by presentation of the point to be determined by trial)," hence "the controversy over facts in a trial" (early 14c., Anglo-French) and transferred sense "point of contention between two parties" (early 15c.) and the general sense "an important point to be decided" (1836). Hence also the verbal phrase take issue with (1797, earlier join issue, 1690s) "take up an affirmative or negative position in a dispute with another." To have issues "have unresolved conflicts" is by 1990.
Old English swa, swæ (adv., conj., pron.) "in this way," also "to that extent; so as, consequently, therefore," and purely intensive; from Proto-Germanic *swa (source also of Old Saxon, Middle Dutch, Old High German so, Old Norse sva, Danish saa, Swedish så, Old Frisian sa, Dutch zo, German so "so," Gothic swa "as"), from PIE reflexive pronominal stem *swo- "so" (source also of Greek hos "as," Old Latin suad "so," Latin se "himself"), derivative of *s(w)e-, pronoun of the third person and reflexive (see idiom).
Old English swa frequently was strengthened by eall, and so also is contained in compounds as, also, such. The -w- was eliminated by contraction from 12c.; compare two, which underwent the same process but retained its spelling.
As a word confirming a previous statement, late Old English; also from late Old English as an intensive in an affirmative clause (such as so very "exceedingly, extremely"). As an "introductory particle" [OED] from 1590s. Used to add emphasis or contradict a negative from 1913. So in mid-20c. British slang could mean "homosexual" (adj.). So? as a term of dismissal is attested from 1886 (short for is that so?, etc.). So what as an exclamation of indifference dates from 1934. Abbreviating phrase and so on is attested from 1724. So far so good is from 1721.