Emily Dickinson Lexicon

MAT'INS, n.

1. Morning worship or service; morning prayers or songs. The vigils are celebrated before them, and the nocturn and matins, for the saints whose the relics are. Stillingfleet. The winged choristers began / To chirp their matins. Cleaveland.
2. Time of morning service; the first canonical hour in the Romish church.