The Collaborative International Dictionary of English v.0.48:

Dentate \Den"tate\ (d[e^]n"t[asl]t), Dentated \Den"ta*ted\
   (d[e^]n"t[asl]*t[e^]d), a. [L. dentatus, fr. dens, dentis,
   tooth.]
   1. (Bot.) Toothed; especially, with the teeth projecting
      straight out, not pointed either forward or backward; as,
      a dentate leaf.
      [1913 Webster]

   2. (Zool.) Having teeth or toothlike points. See Illust. of
      Antenn[ae].
      [1913 Webster]

WordNet (r) 3.0 (2006):

dentate
    adj 1: having toothlike projections in the margin