GNU Collaborative International Dictionary of English

Found one definition 

  1.       

    Requiem , n. [Acc. of L. requies rest, the first words of the Mass being “Requiem aeternam dona eis, Domine,” give eternal rest to them, O lord; pref. re- re + quies quiet. See Quiet, n., and cf. Requin.]
    1. (R.C.Ch.) A mass said or sung for the repose of a departed soul.
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      We should profane the service of the dead
      To sing a requiem and such rest to her
      As to peace-parted souls.
      Shak.

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    2. Any grand musical composition, performed in honor of a deceased person.
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    3. Rest; quiet; peace. [Obs.]
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      Else had I an eternal requiem kept,
      And in the arms of peace forever slept.
      Sandys.

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