The Collaborative International Dictionary of English v.0.48:

Miserere \Mis`e*re"re\, n. [L., have mercy, fr. misereri to have
   mercy, fr. miser. See Miser.]
   [1913 Webster]
   1. (R. C. Ch.) The psalm usually appointed for penitential
      acts, being the 50th psalm in the Latin version. It
      commences with the word miserere.
      [1913 Webster]

   2. A musical composition adapted to the 50th psalm.
      [1913 Webster]

            Where only the wind signs miserere.   --Lowell.
      [1913 Webster]

   3. (Arch.) A small projecting boss or bracket, on the under
      side of the hinged seat of a church stall (see Stall).
      It was intended, the seat being turned up, to give some
      support to a worshiper when standing. Called also
      misericordia.
      [1913 Webster]

   4. (Med.) Same as Ileus.
      [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

39 Moby Thesaurus words for "Miserere":
   Agnus Dei, Benedicite, Gloria, Gloria Patri, Gloria in Excelsis,
   Introit, Magnificat, Nunc Dimittis, Te Deum, Trisagion, Vedic hymn,
   alleluia, answer, anthem, antiphon, antiphony, canticle, chant,
   chorale, doxology, hallelujah, hosanna, hymn, hymn of praise,
   hymnody, hymnography, hymnology, laud, mantra, motet, offertory,
   offertory sentence, paean, psalm, psalmody, report, response,
   responsory, versicle