Origin and history of interspace

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 "amount or extent of time," and in Middle English the word was largely used of time (space of an hour, etc.). Also from early 14c. as "a place;" it is attested from mid-14c. as "distance, interval between two or more objects;" from late 14c. as "ground, land, territory; extension in three dimensions; distance between two or more points." It is recorded by early 15c. as "size, bulk," also "an assigned position."

Typographical sense of "blank type to separate words in print" is attested from 1670s. The typewriter's space-bar is from 1876, earlier space-key (1860).

The astronomical sense of "stellar depths, immense emptiness between the worlds as a characteristic of the universe" is by 1723, perhaps as early as "Paradise Lost" (1667), but common from 1890s.

In this sense a prolific 20c. compound-breeder, many perhaps modeled on earlier ones in air- : Space age is attested from 1946 in reference to the era of human conquest of space but often rather of commercial products that spun off the effort. Many of these first appear in science fiction and speculative writing: spaceship (1894, "A Journey in Other Worlds," John Jacob Astor); spacecraft (1928, Popular Science); space travel (1931); space station "large artificial satellite used as a base for space exploration" (1936, "Rockets Through Space"); space flight (June 1931, Popular Science, from April in newspapers); spaceman (1942, Thrilling Wonder Stories).

Space race in reference to competition among nations to explore space is 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]

Space-saving as an adjective is from 1855 (time-and-space-saving is by 1847). Related: space-saver.

word-forming element used freely in English, "between, among, during," from Latin inter (prep., adv.) "among, between, betwixt, in the midst of" (also used extensively as a prefix), from PIE *enter "between, among" (source also of Sanskrit antar, Old Persian antar "among, between," Greek entera (plural) "intestines," Old Irish eter, Old Welsh ithr "among, between," Gothic undar, Old English under "under"), a comparative of root *en "in."

A living prefix in English from 15c. and used with Germanic as well as Latinate words. Spelled entre- in French; most words borrowed into English in that form were re-spelled 16c. to conform with Latin except entertain, enterprise. In Latin, spelling shifted to intel- before -l-, hence intelligence, etc.