NOUN (1)

1. an unaccompanied partsong for 2 or 3 voices; follows a strict poetic form;


VERB (1)

1. sing madrigals;
- Example: "The group was madrigaling beautifully"

The Collaborative International Dictionary of English v.0.48:

Madrigal \Mad"ri*gal\ (m[a^]d"r[i^]*gal), n. [It. madrigale,
   OIt. madriale, mandriale (cf. LL. matriale); of uncertain
   origin, possibly fr. It mandra flock, L. mandra stall, herd
   of cattle, Gr. ma`ndra fold, stable; hence, madrigal,
   originally, a pastoral song.]
   1. A little amorous poem, sometimes called a pastoral poem,
      containing some tender and delicate, though simple,
      thought.
      [1913 Webster]

            Whose artful strains have oft delayed
            The huddling brook to hear his madrigal. --Milton.
      [1913 Webster]

   2. (Mus.) An unaccompanied polyphonic song, in four, five, or
      more parts, set to secular words, but full of counterpoint
      and imitation, and adhering to the old church modes.
      Unlike the freer glee, it is best sung with several voices
      on a part. See Glee.
      [1913 Webster]

WordNet (r) 3.0 (2006):

madrigal
    n 1: an unaccompanied partsong for 2 or 3 voices; follows a
         strict poetic form
    v 1: sing madrigals; "The group was madrigaling beautifully"

Moby Thesaurus II by Grady Ward, 1.0:

74 Moby Thesaurus words for "madrigal":
   English sonnet, Horatian ode, Italian sonnet, Petrarchan sonnet,
   Pindaric ode, Sapphic ode, Shakespearean sonnet, alba, anacreontic,
   balada, ballad, ballade, bucolic, canso, cantata, chanson,
   choral singing, chorus, clerihew, dirge, dithyramb, eclogue, elegy,
   epic, epigram, epithalamium, epode, epopee, epopoeia, epos,
   georgic, ghazel, glee, haiku, idyll, jingle, limerick, lyric,
   madrigaletto, monody, narrative poem, nursery rhyme, ode, oratorio,
   palinode, pastoral, pastoral elegy, pastorela, pastourelle, poem,
   prothalamium, rhyme, rondeau, rondel, roundel, roundelay, satire,
   sestina, sloka, song, sonnet, sonnet sequence, tanka, tenso,
   tenzone, threnody, triolet, troubadour poem, unison, verse,
   verselet, versicle, villanelle, virelay