The Collaborative International Dictionary of English v.0.48:

Rabbet \Rab"bet\ (r[a^]b"b[e^]t), v. t. [imp. & p. p.
   Rabbeted; p. pr. & vb. n. Rabbeting.] [F. raboter to
   plane, plane down,rabot a plane; pref. re- re- + OF. abouter,
   aboter. See Abut, and cf. Rebut.]
   1. To cut a rabbet in; to furnish with a rabbet.
      [1913 Webster]

   2. To unite the edges of, as boards, etc., in a rabbet joint.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Rabbet \Rab"bet\, n. [See Rabbet, v., and cf. Rebate, n.]
   [1913 Webster]
   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.
      [1913 Webster]

   2. Same as Rabbet joint, below.
      [1913 Webster]

   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.
      [1913 Webster]

WordNet (r) 3.0 (2006):

rabbet
    n 1: a rectangular groove made to hold two pieces together [syn:
         rabbet, rebate]
    v 1: join with a rabbet joint
    2: cut a rectangular groove into

Moby Thesaurus II by Grady Ward, 1.0:

121 Moby Thesaurus words for "rabbet":
   ankle, articulate, articulation, batten, batten down, bezel, bolt,
   boundary, buckle, butt, button, canal, canalize, carve, cervix,
   chamfer, channel, chase, chink, chisel, clasp, cleat, clinch, clip,
   closure, connecting link, connecting rod, connection, corrugate,
   corrugation, coupling, crack, cranny, crimp, cut, dado, dike,
   ditch, dovetail, elbow, embrace, engrave, engraving, flute,
   fluting, furrow, gash, gliding joint, goffer, gouge, groove, gully,
   hasp, hinge, hinged joint, hip, hitch, hook, incise, incision,
   interface, jam, join, joining, joint, juncture, knee, knuckle,
   latch, link, lock, microgroove, miter, mortise, nail, neck, peg,
   pin, pivot, pivot joint, pleat, plow, rifle, rifling, rivet, ruck,
   rut, scarf, score, scratch, screw, seam, sew, shoulder, skewer,
   slit, snap, staple, stick, stitch, streak, stria, striate,
   striation, sulcation, sulcus, suture, symphysis, tack, tie rod,
   toggle, toggle joint, trench, trough, union, wedge, weld,
   well-worn groove, wrinkle, wrist, zipper