/rek"wee euhm, ree"kwee-, ray"-/ , n.
1. Rom. Cath. Ch.
a. Also called Requiem Mass . the Mass celebrated for the repose of the souls of the dead.
b. a celebration of this Mass.
c. a plainsong setting for this Mass.
2. any musical service, hymn, or dirge for the repose of the dead.
Also, requiem .
[ 1275-1325; ME requies rest (the first word of the introit of the mass for the dead) ]