1540s, "to make of a certain extent;" 1680s in typography; 1703 as "to arrange at set intervals," from space (n.). Meaning "to be in a state of drug-induced euphoria" is recorded from 1968. Space cadet "eccentric person disconnected with reality" (often implying an intimacy with hallucinogenic drugs) is a 1960s phrase, probably traceable to 1950s U.S. sci-fi television program "Tom Corbett, Space Cadet," which was watched by many children who dreamed of growing up to be one and succeeded. Related: Spaced; spacing.

"travel on foot," c. 1200, a merger of two verbs, 1. Old English wealcan "to toss, roll, move round" (past tense weolc, past participle wealcen), and 2. wealcian "to roll up, curl," from Proto-Germanic *welk- (source also of Old Norse valka "to drag about," Danish valke "to full" (cloth), Middle Dutch walken "to knead, press, full" (cloth), Old High German walchan "to knead," German walken "to full"), perhaps ultimately from PIE root *wel- (3) "to turn, revolve."

The shift in sense is perhaps from a colloquial use of the Old English word or via the sense of "to full cloth" (by treading on it), though this sense does not appear until after the change in meaning. In 13c. it is used of snakes and the passage of time, and in 15c. of wheeled carts. "Rarely is there so specific a word as NE walk, clearly distinguished from both go and run" [Buck]. Meaning "to go away" is recorded from mid-15c. Transitive meaning "to exercise a dog (or horse)" is from late 15c.; meaning "to escort (someone) in a walk" is from 1620s. Meaning "move (a heavy object) by turning and shoving it in a manner suggesting walking" is by 1890. To walk it off, of an injury, etc., is from 1741. Related: Walked; walking.

c. 1200, "a tossing, rolling;" mid-13c., "an act of walking, a going on foot;" late 14c., "a stroll," also "a path, a walkway;" from walk (v.). The meaning "broad path in a garden" is from 1530s. Meaning "particular manner of walking" is from 1650s. Meaning "manner of action, way of living" is from 1580s; hence walk of life (1733). Meaning "range or sphere of activity" is from 1759. Sports sense of "base on balls" is recorded from 1905; to win in a walk (1854) is from horse racing (see walk-over). As a type of sponsored group trek as a fund-raising event, by 1971 (walk-a-thon is from 1963).

c. 1300, "extent or area; room" (to do something), a shortening of Old French espace "period of time, distance, interval" (12c.), from Latin spatium "room, area, distance, stretch of time," a word of unknown origin (also source of Spanish espacio, Italian spazio).

From early 14c. as "a place," also "amount or extent of time." From mid-14c. as "distance, interval of space;" from late 14c. as "ground, land, territory; extension in three dimensions; distance between two or more points." From early 15c. as "size, bulk," also "an assigned position." Typographical sense is attested from 1670s (typewriter space-bar is from 1876, earlier space-key, 1860).

Astronomical sense of "stellar depths, immense emptiness between the worlds" is by 1723, perhaps as early as "Paradise Lost" (1667), common from 1890s. Space age is attested from 1946. Many compounds first appeared in science fiction and speculative writing, such as spaceship (1894, "A Journey in Other Worlds," John Jacob Astor); spacecraft (1928, Popular Science); space travel (1931); space station (1936, "Rockets Through Space"); spaceman (1942, Thrilling Wonder Stories). Space race attested from 1959. Space shuttle attested by 1970.

Space isn't remote at all. It's only an hour's drive away if your car could go straight upwards. [Sir Fred Hoyle, London Observer, 1979]

c. 1600, from space (n.). Meaning "having to do with outer space" is from 1894.

"easy victory," 1838, such as one that happens in the absence of competitors, when the solitary starter, being obliged to complete the event, can traverse the course at a walk. Transferred sense of "anything accomplished with great ease" is attested from 1902. To walk (all) over (someone) "treat with contempt" is from 1851.

also walkthrough, 1944, "an easy part" (in a theatrical production), from walk (v.) + through. Meaning "dry run, full rehearsal" is from 1959, from the notion of "walking (someone) through" something.

"minor non-speaking role," 1902, theatrical slang, from the verbal phrase walk on, attested in theater jargon by 1897 with a sense "appear in crowd scenes," from walk (v.) + on (adv.). Meaning "actor who has such a part" is attested from 1946. The sports team sense is recorded from 1974.

also airspace, by 1821 in reference to stove and furnace construction, from air (n.1) + space (n.). From 1852 in reference to the cubic contents of a room (with reference to the persons in it) in sanitary regulations for boarding rooms, hospitals, etc. In firearms, "a vacant space between the powder charge and the projectile" (1847). By 1910 as "portion of the atmosphere controlled by a country above its territory."

in reference to an apartment not accessible by elevator, 1909, from the verbal phrase; see walk (v.) + up (adv.). As a noun from 1920 in reference to that type of apartment.