Invitatory /(?)/

In·vi·ta·to·ry

Invitatory

a.
  1. Using or containing invitations.
    The “Venite” [Psalm xcv.], which is also called the invitatory psalm.
    — Hook.

Invitatory

n.

pl. Invitatories

  1. That which invites; specifically, the invitatory psalm, or a part of it used in worship.