Old English weg "road, path; course of travel; room, space, freedom of movement;" also, figuratively, "course of life" especially, in plural, "habits of life" as regards moral, ethical, or spiritual choices, from Proto-Germanic *wega- "course of travel, way" (source also of Old Saxon, Dutch weg, Old Norse vegr, Old Frisian wei, Old High German weg, German Weg, Gothic wigs "way"), from PIE root *wegh- "to go, move, transport in a vehicle."

From c. 1300 as "manner in which something occurs." Adverbial constructions attested since Middle English include this way "in this direction," that way "in that direction," both from late 15c.; out of the way "remote" (c. 1300). In the way "so placed as to impede" is from 1560s.

From the "course of life" sense comes way of life (c. 1600), get (or have) one's way (1590s), have it (one's) way (1709). From the "course of travel" sense comes the figurative go separate ways (1837); one way or (the) other (1550s); have it both ways (1847); and the figurative sense of come a long way (1922).

Adverbial phrase all the way "completely, to conclusion" is by 1915; sexual sense implied by 1924. Make way is from c. 1200. Ways and means "resources at a person's disposal" is attested from early 15c. (with mean (n.)). Way out "means of exit" is from 1926. Encouragement phrase way to go is short for that's the way to go.

1767, "legal right, established by usage, to pass across grounds or property belonging to another." Of the path itself from 1805. By 1913 as "legal right of a pedestrian or vehicle to have precedence at a crossing or convergence." 

1824, "leading in one direction only;" by 1887 in reference to travel tickets or fares; 1914 in reference to streets; 1940 in reference to windows, mirrors, etc.; from one + way (n.).

"the galaxy as seen in the night sky," late 14c., loan-translation of Latin via lactea; see galaxy. Formerly in Middle English also Milken-Way and Milky Cercle. The ancients speculated on what it was; some guessed it was a vast assemblage of stars (Democrates, Pythagoras, even Ovid); the question was settled when Galileo, using his telescope, reported that the whole of it was resolvable into stars. Old native names for it include Jacob's Ladder, the Way to St. James's, and Watling Street (late 14c.).