Source : Webster's Revised Unabridged Dictionary (1913)

Ski \Ski\, n.
   Same as {Skee}.

Source : WordNet®

ski
     n : narrow wood or metal or plastic runners used for gliding
         over snow [syn: {skis}]
     [also: {ski'd}]

ski
     v : move along on skis; "We love to ski the Rockies"
     [also: {ski'd}]