Source : Webster's Revised Unabridged Dictionary (1913)

Rabbet \Rab"bet\, n. [See {Rabbet} v., and cf. {Rebate}, n.]
   1. (Carp.) A longitudinal channel, groove, or recess cut out
      of the edge or face of any body; especially, one intended
      to receive another member, so as to break or cover the
      joint, or more easily to hold the members in place; thus,
      the groove cut for a panel, for a pane of glass, or for a
      door, is a rabbet, or rebate.

   2. Same as Rabbet joint, below.

   {Rabbet joint} (Carp.), a joint formed by fitting together
      rabbeted boards or timbers: -- called also {rabbet}.

   {Rabbet plane}, a joiner's plane for cutting a rabbet.
      --Moxon.

Source : WordNet®

rabbet joint
     n : a joint formed by fitting together two rabbeted boards