The Collaborative International Dictionary of English v.0.48:

Choral \Cho"ral\, chorale \chorale\, n. (Mus.)
   A stately hymn tune; a simple sacred tune, sung in unison by
   the congregation, used mostly in Protestant (especially
   Lutheran) churches; as, the Lutheran chorals. [Sometimes
   written chorale.]
   [1913 Webster + WordNet 1.5]

WordNet (r) 3.0 (2006):

chorale
    n 1: a stately Protestant (especially Lutheran) hymn tune [syn:
         chorale, choral]

Moby Thesaurus II by Grady Ward, 1.0:

71 Moby Thesaurus words for "chorale":
   Agnus Dei, Benedicite, Gloria, Gloria Patri, Gloria in Excelsis,
   Introit, Liederkranz, Liedertafel, Magnificat, Miserere,
   Negro spiritual, Nunc Dimittis, Te Deum, Trisagion, Vedic hymn,
   a cappella, alleluia, answer, anthem, antiphon, antiphony, cantata,
   canticle, chamber chorus, chant, choir, choral group,
   choral society, choral symphony, chorus, church music, doxology,
   ensemble, glee club, gospel, gospel music, hallelujah, hosanna,
   hymn, hymn of praise, hymn-tune, hymnody, hymnography, hymnology,
   introit, laud, mantra, mass, mixed chorus, motet, offertory,
   offertory sentence, oratorio, oratorio society, paean, passion,
   prosodion, psalm, psalmody, recessional, report, requiem,
   requiem mass, response, responsory, sacred music, singing club,
   spiritual, versicle, voices, white spiritual