/mas/ , n.
1. the celebration of the Eucharist. Cf. High Mass, Low Mass .
2. ( sometimes l.c. ) a musical setting of certain parts of this service, as the Kyrie eleison, Gloria, Credo, Sanctus, Benedictus, and Agnus Dei.
[ bef. 900; ME masse, OE maesse messa, LL missa, formally fem. of L missus, ptp. of mittere to send, dismiss; perh. extracted from a phrase in the service with missa est and a fem. subject ]