The Collaborative International Dictionary of English v.0.48:

Timpano \Tim"pa*no\, n.; pl. Timpani. [It.] (Mus.)
   See Tympano.
   [1913 Webster] Timur

WordNet (r) 3.0 (2006):

timpani
    n 1: a large hemispherical brass or copper percussion instrument
         with a drumhead that can be tuned by adjusting the tension
         on it [syn: kettle, kettledrum, tympanum, tympani,
         timpani]

Moby Thesaurus II by Grady Ward, 1.0:

27 Moby Thesaurus words for "timpani":
   bongo drum, conga, drum, drumhead, drumskin, drumstick, jazz stick,
   kettle, kettledrum, membranophone, side drum, snare, snare drum,
   tabor, taboret, tabret, tam-tam, tambourine, tenor drum, timbrel,
   tom-tom, troll-drum, tymp stick, tympan, tympanon, tympanum,
   war drum