The Collaborative International Dictionary of English v.0.48:

Crenelate \Cren"el*ate\ (kr?n"?l-?t or kr?"n?l-?t), v. t. [imp.
   & p. p. Crenelated (-?`t?d); p. pr. & vb. n. Crenelating
   (-?`t?ng).] [LL. crenellare, kernellare: cf. F. cr?neler to
   indent. See Crenelle.] [Written also crenellate.]
   1. To furnish with crenelles.
      [1913 Webster]

   2. To indent; to notch; as, a crenelated leaf.
      [1913 Webster]

   Crenelated molding (Arch.), a kind of indented molding used
      in Norman buildings.
      [1913 Webster]

WordNet (r) 3.0 (2006):

crenelate
    v 1: supply with battlements [syn: crenel, crenelate,
         crenellate]