MASS n.
usic, the assistance of a deacon, subdeacon, etc. -- Low Mass, Mass which is said by the priest through-out, without music. -- Mass bell, the sanctus bell. See Sanctus. -- Mass book, the missal or Roman Catholic service book.
ORDER n.
An ecclesiastical grade or rank, as of deacon, priest, or bishop; the office of the Christian ministry; -- often used in the plural; as, to take orders, or to take holy orders, that is, to enter some grade of the ministry.