In*voke" (?), v. t. [imp. & p. p. Invoked (?); p. pr. & vb. n. Invoking.] [F. invoquer, L. invocare; pref. in- in, on + vocare to call, fr. vox voice. See Voice, and cf. Invocate.] To call on for aid or protection; to invite earnestly or solemnly; to summon; to address in prayer; to solicit or demand by invocation; to implore; as, to invoke the Supreme Being, or to invoke His and blessing.

Go, my dread lord, to your great grandsire's tomb, . . .
Invoke his warlike spirit.

• to call upon someone for help, assistance or guidance, especially upon a god
  
• to conjure up with incantations
  
• (computing) to call a program or subroutine