The Collaborative International Dictionary of English v.0.48:

Aculeate \A*cu"le*ate\, a. [L. aculeatus, fr. aculeus, dim. of
   acus needle.]
   1. (Zool.) Having a sting; covered with prickles; sharp like
      a prickle.
      [1913 Webster]

   2. (Bot.) Having prickles, or sharp points; beset with
      prickles.
      [1913 Webster]

   3. Severe or stinging; incisive. [R.] --Bacon.
      [1913 Webster]

WordNet (r) 3.0 (2006):

aculeate
    adj 1: having or resembling a stinger or barb; "aculeate insects
           such as bees and wasps" [syn: aculeate, aculeated]