Origin and history of *spek-

late 14c., an astrological term, "relative position of the planets as they appear from earth" (i.e., how they "look at" one another); also "one of the ways of viewing something," from Latin aspectus "a seeing, looking at, sight, view; countenance; appearance," from past participle of aspicere "to look at, look upon, behold; observe, examine," figuratively "consider, ponder," from ad "to" (see ad-) + specere "to look" (from PIE root *spek- "to observe").

The meanings "the look one wears" and "the appearance of things" are attested by early 15c. The sense of "a facing in a given direction" is from 1660s.

"one who observes flights of birds for the purpose of taking omens," 1590s, from Latin auspex "interpreter of omens given by birds," from PIE *awi-spek- "observer of birds," from root *awi- "bird" + root *spek- "to observe." Compare Greek oionos "bird of prey," also "bird of omen, omen," and ornis "bird," which also could mean "omen."