The Collaborative International Dictionary of English v.0.48:

Panicle \Pan"i*cle\, n. [L. panicula a tuft on plants, dim. of
   panus the thread wound upon the bobbin in a shuttle; cf. Gr.
   ?, ?; prob. akin to E. pane: cf. F. panicule. See 2d Pane.]
   (Bot.)
   A pyramidal form of inflorescence, in which the cluster is
   loosely branched below and gradually simpler toward the end.
   [1913 Webster]

WordNet (r) 3.0 (2006):

panicle
    n 1: compound raceme or branched cluster of flowers