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.

c. 1200, short for away (adv.). Many expressions involving this are modern and American English colloquial, such as way-out "far off;" way back "a long time ago" (1887); way off "quite wrong" (1892). Any or all of these might have led to the slang adverbial meaning "very, extremely," attested by 1984 (as in way cool).

"passageway between buildings," 1850, from area + way (n.).

also cartway, "road on which carts may travel," mid-14c., from cart (n.) + way (n.).

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.).

1868, "far off," from way (adv.), short for away, + out. Sense of "original, bold," is jazz slang from 1940s, probably suggesting "far off" from what is conventional or expected.

also sideway, 1550s, "byway, path or way along the side of or diverging from a main road," from side (n.) + way (n.). Compare German Seitenweg. By 1738 as "sidewalk."

prehistoric trackway from Norfolk to Dorset, Old English Iccenhilde, Icenhylte (903), which is of unknown meaning and origin. There was a Romano-British Iceni tribe in modern Norfolk. The name was transferred 12c. to the ancient Roman road from Burton on the Water to Templeborough.

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." 

1930, from free (adj.) + way (n.).