mid-14c., "specially prepared or arranged display," from Old French spectacle "sight, spectacle, Roman games" (13c.), from Latin spectaculum "a public show, spectacle, place from which shows are seen," from spectare "to view, watch, behold," frequentative form of specere "to look at" (from PIE root *spek- "to observe").
"glass lenses to help a person's sight," early 15c., from plural of spectacle. Earlier in singular form (late 14c.).
1580s, from Latin spectator "viewer, watcher," from past participle stem of spectare "to view, watch" (see spectacle). Spectator sport is attested from 1943. Related: Spectatorial. Fem. form spectatress (1630s) is less classically correct than spectatrix (1610s).
Proto-Indo-European root meaning "to observe."
It forms all or part of: aspect; auspex; auspices; auspicious; bishop; circumspect; conspicuous; despicable; despise; episcopal; especial; espionage; espy; expect; frontispiece; gyroscope; haruspex; horoscope; inspect; inspection; inspector; introspect; introspection; perspective; perspicacious; perspicacity; prospect; prospective; respect; respite; retrospect; scope; -scope; scopophilia; -scopy; skeptic; species; specimen; specious; spectacle; spectacular; spectrum; speculate; speculation; speculum; spice; spy; suspect; suspicion; suspicious; telescope.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit spasati "sees;" Avestan spasyeiti "spies;" Greek skopein "behold, look, consider," skeptesthai "to look at," skopos "watcher, one who watches;" Latin specere "to look at;" Old High German spehhon "to spy," German spähen "to spy."
"features of a place that are deemed worth seeing," 1630s, plural of sight (n.) in the sense of "a spectacle seen" (c. 1200)..
noun suffix meaning "sight, view, spectacular display or instance of," 1824, abstracted from panorama (q.v.), ultimately from Greek horama "sight, spectacle, that which is seen."
"demonstrable proposition in science or mathematics," 1550s, from French théorème (16c.) and directly from Late Latin theorema, from Greek theorema "spectacle, sight," in Euclid "proposition to be proved," literally "that which is looked at," from theorein "to look at, behold" (see theory).