The Collaborative International Dictionary of English v.0.48:

Coriaceous \Co`ri*a"ceous\ (k?`r?-?"sh?s), a. [L. coriaceous,
   fr. corium leather. See Cuirass.]
   1. Consisting of or resembling, leather; leatherlike; tough.
      [1913 Webster]

   2. (Bot.) Stiff, like leather or parchment.
      [1913 Webster]

WordNet (r) 3.0 (2006):

coriaceous
    adj 1: resembling or made to resemble leather; tough but pliable
           [syn: coriaceous, leathered, leatherlike,
           leathery]