The Collaborative International Dictionary of English v.0.48:

Beetle \Bee"tle\, n. [OE. bityl, bittle, AS. b[imac]tel, fr.
   b[imac]tan to bite. See Bite, v. t.]
   Any insect of the order Coleoptera, having four wings, the
   outer pair being stiff cases for covering the others when
   they are folded up. See Coleoptera.
   [1913 Webster]

   Beetle mite (Zool.), one of many species of mites, of the
      family Oribatid[ae], parasitic on beetles.

   Black beetle, the common large black cockroach (Blatta
      orientalis).
      [1913 Webster]