• The sacrifice in the sacrament of the Eucharist, or the consecration and oblation of the host. • The portions of the Mass usually set to music, considered as a musical composition; -- namely, the Kyrie, the Gloria, the Credo, the Sanctus, and the Agnus Dei, besides sometimes an Offertory and the Benedictus. • To celebrate Mass. • A quantity of matter cohering together so as to make one body, or an aggregation of particles or things which collectively make one body or quantity, usually of considerable size; as, a mass of ore, metal, sand, or water. • A medicinal substance made into a cohesive, homogeneous lump, of consistency suitable for making pills; as, blue mass. • A large quantity; a sum. • Bulk; magnitude; body; size. • The principal part; the main body. • The quantity of matter which a body contains, irrespective of its bulk or volume. • To form or collect into a mass; to form into a collective body; to bring together into masses; to assemble.