The Collaborative International Dictionary of English v.0.48:

corncob \corn"cob`\ (k[^o]rn"k[o^]b`), n.
   The cob or axis on which the kernels of Indian corn grow.
   [U.S.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

corncob
    n 1: the hard cylindrical core that bears the kernels of an ear
         of corn [syn: corncob, corn cob]

Moby Thesaurus II by Grady Ward, 1.0:

25 Moby Thesaurus words for "corncob":
   Missouri meerschaum, auricle, briar, briar pipe, calean, calumet,
   churchwarden, clay, cob, corncob pipe, ear, ear of corn, hookah,
   hubble-bubble, mealie, meerschaum, nargileh, peace pipe, pipe,
   pipe cleaner, pipe rack, spike, tobacco pipe, tobacco pouch,
   water pipe