The Collaborative International Dictionary of English v.0.48:

Cresting \Crest"ing\, n. (Arch.)
   An ornamental finish on the top of a wall or ridge of a roof.
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The Collaborative International Dictionary of English v.0.48:

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.
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            His legs bestrid the ocean, his reared arm
            Crested the world.                    --Shak.
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            Mid groves of clouds that crest the mountain's brow.
                                                  --Wordsworth.
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   2. To mark with lines or streaks, like, or regarded as like,
      waving plumes.
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            Like as the shining sky in summer's night, . . .
            Is crested with lines of fiery light. --Spenser.
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