The Collaborative International Dictionary of English v.0.48:

Clathrate \Clath"rate\ (kl[a^]th"r[asl]t), a. [L. clathri
   lattice, Gr. klh,qra.]
   1. (Bot.) Shaped like a lattice; cancellate. --Gray.
      [1913 Webster]

   2. (Zool.) Having the surface marked with raised lines
      resembling a lattice, as many shells.
      [1913 Webster]

WordNet (r) 3.0 (2006):

clathrate
    adj 1: having a latticelike structure pierced with holes or
           windows [syn: cancellate, cancellated, clathrate]
    2: designating or relating to a compound in which one component
       is physically enclosed within the crystal structure of
       another