"one who tests, puts to trial, or assays," 1660s, agent noun from test (v.). Earlier "a crucible" for trying metals by heating them (mid-15c.).

"canopy over a four-post bed," mid-14c., from Medieval Latin testerium, from testera "head-stall" of the bridle of a horse, extended use and form of Late Latin testa "skull," in Vulgar Latin "head" (see tete). From Medieval Latin testa as "head" also come tester in obsolete senses of "piece of armor for the head" (late 14c., via Old French testiere) and "coin of Henry VIII" (1546), the first English coin to bear a true portrait.

1922, American English colloquial, of uncertain origin, perhaps related to slang tizzy "sixpence piece" (1804), a corruption of tester, a name for the coin (see tester (n.2)).

mid-14c., screne, "upright piece of furniture providing protection from heat of a fire, drafts, etc.," probably from a shortened (Anglo-French? compare Anglo-Latin screna) variant of Old North French escren, Old French escran "fire-screen, tester of a bed" (early 14c.). This is of uncertain origin, though probably from a Germanic source, perhaps from Middle Dutch scherm "screen, cover, shield," or Frankish *skrank "barrier," from Proto-Germanic *skirmjanan(source also of Old High German skirm, skerm "protection," Old Frisian skirma "protect, defend;" from PIE root *sker- (1) "to cut").

The sense of "anything interposed to conceal from view" is by c. 1600. The meaning "net-wire frame used in windows and doors" is recorded from 1859. Meaning "flat vertical surface for reception of projected images" is from 1810, originally in reference to magic lantern shows; later of movies. Transferred sense of "cinema world collectively" is attested from 1914; hence screen test "filmed test of performing abilities" (1918), etc.

The meaning "small fluorescent display on a TV set" is by 1946, extended to the display on a computer monitor by 1970, hence the monitor itself. The computer screen saver is attested by 1990. The meaning "window of an automobile" is by 1904. As a type of maneuver in sports, by 1934 (U.S. football, screen-pass). Screen printing recorded from 1918. Screen-door is from 1840. Screen-time "time spent watching a computer or television screen" is by 1999.