The Collaborative International Dictionary of English v.0.48:

Lappet \Lap"pet\, n. [Dim. of lap a fold.]
   A small decorative fold or flap, esp. of lace or muslin, in a
   garment or headdress. --Swift.
   [1913 Webster]

   Lappet moth (Zool.), one of several species of bombycid
      moths, which have stout, hairy caterpillars, flat beneath.
      Two common American species (Gastropacha Americana, and
      Tolype velleda) feed upon the apple tree.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Lappet \Lap"pet\, v. t. [imp. & p. p. Lappeted; p. pr. & vb.
   n. Lappeting.]
   To decorate with, or as with, a lappet. [R.] --Landor.
   [1913 Webster]

WordNet (r) 3.0 (2006):

lappet
    n 1: a fleshy wrinkled and often brightly colored fold of skin
         hanging from the neck or throat of certain birds (chickens
         and turkeys) or lizards [syn: wattle, lappet]
    2: a small lap on a garment or headdress
    3: medium-sized hairy moths; larvae are lappet caterpillars
       [syn: lappet, lappet moth]

Moby Thesaurus II by Grady Ward, 1.0:

31 Moby Thesaurus words for "lappet":
   crease, creasing, crimp, dog-ear, double, doubling, drape,
   duplicature, ear lobe, flection, flexure, flounce, fold, frill,
   gather, hanger, hanging, lapel, lobation, lobe, lobule, pendant,
   plica, plication, plicature, ply, ruche, ruching, ruffle, tuck,
   uvula