It forms all or part of: awake; bewitch; bivouac; invigilate; reveille; surveillance; vedette; vegetable; velocity; vigil; vigilant; vigilante; vigor; waft; wait; wake (v.) "emerge or arise from sleep;" waken; watch; Wicca; wicked; witch.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit vajah "force, strength," vajayati "drives on;" Latin vigil "watchful, awake," vigere "be lively, thrive," velox "fast, lively," vegere "to enliven," vigor "liveliness, activity;" Old English wacan "to become awake," German wachen "to be awake," Gothic wakan "to watch."
c. 1600, "act of bewitching," from Latin fascinationem (nominative fascinatio), noun of action from past-participle stem of fascinare "bewitch, enchant" (see fascinate). Meaning "state of being fascinated" is from 1650s; that of "fascinating quality, attractive influence upon the attention" is from 1690s.
late 14c., literal ("practice sorcery or witchcraft on") and figurative ("delight in a high degree, charm, fascinate"), from Old French enchanter "bewitch, charm, cast a spell" (12c.), from Latin incantare "to enchant, fix a spell upon," from in- "upon, into" (from PIE root *en "in") + cantare "to sing" (from PIE root *kan- "to sing"). Or perhaps a back-formation from enchantment.
mid-15c., "false accusation, slander," from Old French calomnie (15c.), from Latin calumnia "trickery, subterfuge, misrepresentation, malicious charge," from calvi "to trick, deceive."
PIE cognates include Greek kelein "to bewitch, cast a spell," Gothic holon "to slander," Old Norse hol "praise, flattery," Old English hol "slander," holian "to betray," Old High German huolen "to deceive." The whole group is perhaps from the same root as call (v.). A doublet of challenge.
"art or act of enchanting by uttering magical words, with ceremonies supposed to have magical power; the formula of words or the ceremony employed," late 14c., from Old French incantacion "spell, exorcism" (13c.), from Late Latin incantationem (nominative incantatio) "art of enchanting," noun of action from past-participle stem of incantare "to bewitch, charm, cast a spell upon, chant magic over, sing spells" (see enchantment).
c. 1300, enchauntement, "act of magic or witchcraft; use of magic; magic power," from Old French encantement "magical spell; song, concert, chorus," from enchanter "bewitch, charm," from Latin incantare "enchant, cast a (magic) spell upon," from in- "upon, into" (from PIE root *en "in") + cantare "to sing" (from PIE root *kan- "to sing"). Figurative sense of "allurement" is from 1670s. Compare Old English galdor "song," also "spell, enchantment," from galan "to sing," which also is the source of the second element in nightingale.