Source : Webster's Revised Unabridged Dictionary (1913)

Crest \Crest\, v. t. [imp. & p. p. {Crested}; p. pr. & vb. n.
   {Cresting}.]
   1. To furnish with, or surmount as, a crest; to serve as a
      crest for.

Cresting \Crest"ing\, n. (Arch.)
   An ornamental finish on the top of a wall or ridge of a roof.