Source : Webster's Revised Unabridged Dictionary (1913)

Lapel \La*pel"\, n. [Dim. of lap a fold.]
   That part of a garment which is turned back; specifically,
   the lap, or fold, of the front of a coat in continuation of
   collar. [Written also {lappel} and {lapelle}.]

Source : WordNet®

lapel
     n : lap at the front of a coat; continuation of the coat collar