The Collaborative International Dictionary of English v.0.48:

Scallop \Scal"lop\, v. t. [imp. & p. p. Scalloped; p. pr. &
   vb. n. Scalloping.]
   1. To mark or cut the edge or border of into segments of
      circles, like the edge or surface of a scallop shell. See
      Scallop, n., 2.
      [1913 Webster]

   2. (Cookery) To bake in scallop shells or dishes; to prepare
      with crumbs of bread or cracker, and bake. See Scalloped
      oysters, below.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Scalloped \Scal"loped\, a.
   1. Furnished with a scallop; made or done with or in a
      scallop.
      [1913 Webster]

   2. Having the edge or border cut or marked with segments of
      circles. See Scallop, n., 2.
      [1913 Webster]

   3. (Cookery) Baked in a scallop; cooked with crumbs.
      [1913 Webster]

   Scalloped oysters (Cookery), opened oysters baked in a deep
      dish with alternate layers of bread or cracker crumbs,
      seasoned with pepper, nutmeg, and butter. This was at
      first done in scallop shells.
      [1913 Webster]

WordNet (r) 3.0 (2006):

scalloped
    adj 1: having a margin with rounded scallops [syn: crenate,
           crenated, scalloped]