The Collaborative International Dictionary of English v.0.48:

Striatum \Stri*a"tum\, n. [NL.] (Anat.)
   The corpus striatum.
   [1913 Webster]

WordNet (r) 3.0 (2006):

striatum
    n 1: a striped mass of white and grey matter located in front of
         the thalamus in each cerebral hemisphere; consists of the
         caudate nucleus and the lenticular nucleus [syn: corpus
         striatum, striatum, striate body]