incantation n.

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.

Proto-Indo-European root meaning "to sing."

It forms all or part of: accent; cant (n.1); cantabile; cantata; cantatrice; canticle; canto; cantor; canzone; Carmen; chanson; chant; chanter; chanteuse; chanty; chanticleer; charm; concent; descant; enchant; enchantment; hen; incantation; incentive; oscine; precentor; recant.

It is the hypothetical source of/evidence for its existence is provided by: Greek eikanos "cock," literally "bird who sings (for sunrise);" Latin cantare, canere "to sing;" Old Irish caniaid "sings," Welsh canu "sing;" Old English hana "cock."