The Collaborative International Dictionary of English v.0.48:

Cancellate \Can"cel*late\, a. [L. cancellatus, p. p. of
   cancellare, See Cancel, v. t.]
   1. (Bot.) Consisting of a network of veins, without
      intermediate parenchyma, as the leaves of certain plants;
      latticelike.
      [1913 Webster]

   2. (Zool.) Having the surface coveres with raised lines,
      crossing at right angles.
      [1913 Webster]

WordNet (r) 3.0 (2006):

cancellate
    adj 1: having a latticelike structure pierced with holes or
           windows [syn: cancellate, cancellated, clathrate]
    2: having an open or latticed or porous structure [syn:
       cancellate, cancellated, cancellous]