Webster’s Revised Unabridged Dictionary · 1913
Invitatory
In·vi′ta·to·ry (ĭn·vī′tȧ·tō·ry̆), a. [L. invitatorius: cf. F. invitatoire.] Using or containing invitations.
The "Venite" [Psalm xcv.], which is also called the invitatory psalm. Hook.
In·vi′ta·to·ry, n.; pl. Invitatories (#). [LL. invitatorium: cf. F. invitatoire.] That which invites; specifically, the invitatory psalm, or a part of it used in worship.