%introit%

n. [ L. introitus, fr. introire to go into, to enter; intro within + ire to go: cf. F. introit. ] [ 1913 Webster ]

1. A going in. Caxton. [ 1913 Webster ]

2. (R. C. Ch.) (a) A psalm sung or chanted immediately before the collect, epistle, and gospel, and while the priest is entering within the rails of the altar. (b) A part of a psalm or other portion of Scripture read by the priest at Mass immediately after ascending to the altar. [ 1913 Webster ]

3. (R. C. Ch.) An anthem or psalm sung before the Communion service. [ 1913 Webster ]

4. Any composition of vocal music appropriate to the opening of church services. [ 1913 Webster ]