"extent," 1530s, "room to act," from Italian scopo "aim, purpose, object, thing aimed at, mark, target," from Latin scopus, from Greek skopos "aim, target, watcher," from PIE *spek- "to observe" (cf. Sanskrit spasati "sees;" Avestan spasyeiti "spies;" Greek skopein "behold, look, consider," skeptesthai "to look at;" Latin specere "to look at;" Old High German spehhon "to spy," German spähen "to spy"). Sense of "distance the mind can reach, extent of view" first recorded c.1600.
"instrument for viewing," 1872, abstracted from telescope, microscope, etc., from Greek skopein "to look" (see scope (n.1)). Earlier used as a shortening of horoscope (c.1600).
"to view," 1807, from the source of scope (n.2). Related: Scoped; scoping.