Definify.com
Webster 1913 Edition
Requiem
Re′qui-em
(r?′kw?-?m;277)
, Noun.
 1. 
(R.C.Ch.) 
A mass said or sung for the repose of a departed soul. 
We should profane the service of the dead
To sing a
As to peace-parted souls.
To sing a
requiem 
and such rest to herAs to peace-parted souls.
Shakespeare
2. 
Any grand musical composition, performed in honor of a deceased person. 
3. 
Rest; quiet; peace. 
[Obs.] 
Else had I an eternal 
And in the arms of peace forever slept.
requiem 
kept,And in the arms of peace forever slept.
Sandys.
Webster 1828 Edition
Requiem
RE'QUIEM
,Noun.
  1.
  In the Romish church, a hymn or mass sung for the dead, for the rest of his soul; so called from the first word.2.
  Rest; quiet; peace.  [Not in use.]