MASS(2) - n.
(often Mass)
1 the Eucharist, esp. in the Roman Catholic Church.
2 a celebration of this.
3 the liturgy used in the mass.
4 a musical setting of parts of this.

high mass mass with incense, music, and usu. the assistance of a deacon and subdeacon. low mass mass with no music and a minimum of ceremony. [OE mósse f. eccl.L missa f. L mittere miss- dismiss, perh. f. the concluding dismissal Ite, missa est Go, it is the dismissal]