Lewis & Short

invītātor, ōris, m. [invito],

  1. I. one who invites, an inviter (poet. and post-class.), Mart. 3, 23 lemm.; Sid. Ep. 9, 13; Tert. adv. Marc. 4, 25: aeternae vitae invitator, Christus, id. ib.
  2. II. Esp., the officer charged with invitations at the court, Cod. 12, 60, 10; Inscr. Orell. 4436: Caesaris, Jovis, Mart. 9, 91, 2.