Source : Webster's Revised Unabridged Dictionary (1913)

Pyramidal \Py*ram"i*dal\, n. (Anat.)
   One of the carpal bones. See {Cuneiform}, n., 2
   (b) .

Pyramidal \Py*ram`i*dal\, a. [Cf. F. pyramidal.]
   1. Of or pertaining to a pyramid; in the form of a a pyramid;
      pyramidical; as, pyramidal cleavage.

            The mystic obelisks stand up Triangular, pyramidal.
                                                  --Mrs.
                                                  Browning.

Source : WordNet®

pyramidal
     adj : resembling a pyramid [syn: {pyramidic}, {pyramidical}]