in·vi·ta·to·ry 
(ĭn-vītə-tôr′ē)
(ĭn-vītə-tôr′ē)n. pl. in·vi·ta·to·ries
A psalm or other piece sung as an invitation to prayer in church services, especially at the opening of matins in the Roman office.
adj.
Constituting or containing an invitation.
[Middle English invitatorie, from Medieval Latin invītātōrium, from Late Latin invītātōrius, inviting, from Latin invītātus, past participle of invītāre, to invite.]
- quadriphonic
- quadriphony
- quadriplegia
- quadriplegic
- quadrivalence
- quadrivalency
- quadrivalent
- quadrivium
- quadroon
- quadru-
- quadru-
- quadrumanal
- quadrumanous
- quadrumvirate
- quadruped
- quadruped
- quadrupedal
- quadrupedalism
- quadrupedally
- quadruple
- quadruplet
- quadruple witching hour
- quadruplicate
- quadruplicately
- quadruplication