Source : Webster's Revised Unabridged Dictionary (1913)

Waterfall \Wa"ter*fall`\, n.
   1. A fall, or perpendicular descent, of the water of a river
      or stream, or a descent nearly perpendicular; a cascade; a
      cataract.

   2. (Hairdressing) An arrangement of a woman's back hair over
      a cushion or frame in some resemblance to a waterfall.

Source : WordNet®

waterfall
     n : a steep descent of the water of a river [syn: {falls}]