An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

1) to call for with earnest desire; make supplication or pray for.
2) to call on (a deity, Muse, etc.), as in prayer or supplication.
3) To declare to be binding or in effect (to invoke the law; to invoke a veto).
4) To appeal to, as for confirmation.
5) To petition or call on for help or aid.

M.E., from M.Fr. envoquer, from L. invocare "call upon, implore," from → in- "upon" + vocare "to call," from vox, → voice.

Darvacidan, from dar-, → in-, + vacidan "to call," rarr; convoke.