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."

1917, from air (n.1) + force (n.); first attested with creation of the Royal Air Force. There was no United States Air Force until after World War II. The Air Corps was an arm of the U.S. Army. In 1942, the War Department reorganized it and renamed it Army Air Forces. The National Security Act of 1947 created the Department of the Air Force, headed by a Secretary of the Air Force, and the U.S.A.F.

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.

c. 1300, "order or direct with authority" (transitive), from Old French comander "to order, enjoin, entrust" (12c., Modern French commander), from Vulgar Latin *commandare, from Latin commendare "to recommend, entrust to" (see commend); altered by influence of Latin mandare "to commit, entrust" (see mandate (n.)). In this sense Old English had bebeodan.

Intransitive sense "act as or have authority of a commander, have or exercise supreme power" is from late 14c. Also from late 14c. as "have within the range of one's influence" (of resources, etc.), hence, via a military sense, "have a view of, overlook" in reference to elevated places (1690s). Related: Commanded; commanding.

Command-post "headquarters of a military unit" is from 1918. A command performance (1863) is one given by royal command.

c. 1400, "an order, a command; what is commanded or ordered," from Old French comand (14c.), from comander "to order, to entrust" (see command (v.)). Meaning "control, right or authority to order or compel obedience" is from mid-15c. Meaning "power of control, mastery" (of a situation, a language, etc.) is from 1640s.

c. 1300, "physical strength," from Old French force "force, strength; courage, fortitude; violence, power, compulsion" (12c.), from Vulgar Latin *fortia (source also of Old Spanish forzo, Spanish fuerza, Italian forza), noun use of neuter plural of Latin fortis "strong, mighty; firm, steadfast; brave, bold" (see fort).

Meanings "power to convince the mind" and "power exerted against will or consent" are from mid-14c. Meaning "body of armed men, a military organization" first recorded late 14c. (also in Old French). Physics sense is from 1660s; force field attested by 1920. Related: Forces.

c. 1300, forcen, also forsen, "exert force upon (an adversary)," from Old French forcer "conquer by violence," from force "strength, power, compulsion" (see force (n.)). From early 14c. as "to violate (a woman), to rape." From c. 1400 as "compel by force, constrain (someone to do something)." Meaning "bring about by unusual effort" is from 1550s. Card-playing sense is from 1746 (whist). Related: Forced; forcing.

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.

"melody, tune, connected rhythmic succession of distinct musical sounds," 1580s, nativized from Italian aria (see aria), perhaps via French.