The Collaborative International Dictionary of English v.0.48:

Silique \Sil"ique\, n. [L. siliqua a pod or husk, a very small
   weight or measure: cf. F. silique.] (Bot.)
   An oblong or elongated seed vessel, consisting of two valves
   with a dissepiment between, and opening by sutures at either
   margin. The seeds are attached to both edges of the
   dissepiment, alternately upon each side of it.
   [1913 Webster]

WordNet (r) 3.0 (2006):

silique
    n 1: narrow elongated seed capsule peculiar to the family
         Cruciferae [syn: silique, siliqua]