Source : Webster's Revised Unabridged Dictionary (1913)

Cleat \Cleat\ (kl[=e]t), n. [OE. clete wedge; cf. D. kloot ball,
   Ger. kloss, klotz, lump. clod, MHG. kl[=o]z lump, ball,
   wedge, OHG. chl[=o]z ball, round mass.]
   1. (Carp.) A strip of wood or iron fastened on transversely
      to something in order to give strength, prevent warping,
      hold position, etc.

   2. (Naut.) A device made of wood or metal, having two arms,
      around which turns may be taken with a line or rope so as
      to hold securely and yet be readily released. It is bolted
      by the middle to a deck or mast, etc., or it may be lashed
      to a rope.

Cleat \Cleat\, v. t.
   To strengthen with a cleat.

Source : WordNet®

cleat
     n 1: a metal or leather projection (as from the sole of a shoe);
          prevents slipping
     2: a fastener (usually with two projecting horns) around which
        a rope can be secured
     3: a strip of wood or metal used to strengthen the surface to
        which it is attached

cleat
     v 1: provide with cleats; "cleat running shoes for better
          traction"
     2: secure on a cleat; "cleat a line"