The Collaborative International Dictionary of English v.0.48:

Colza \Col"za\, n. [F., fr. D. koolzaad, prop., cabbage seed;
   kool (akin to E. cole) + zaad, akin to E. seed.] (Bot.)
   A variety of cabbage (Brassica oleracea), cultivated for
   its seeds, which yield an oil valued for illuminating and
   lubricating purposes; summer rape.
   [1913 Webster]

WordNet (r) 3.0 (2006):

colza
    n 1: Eurasian plant cultivated for its seed and as a forage crop
         [syn: rape, colza, Brassica napus]