The Collaborative International Dictionary of English v.0.48:

Hectometer \Hec"to*me`ter\, Hectometre \Hec"to*me`tre\, n. [F. ?
   hectom[`e]tre, fr. Gr. ? hundred + F. m[`e]tre a meter.]
   A measure of length, equal to a hundred meters. It is
   equivalent to 328.09 feet.
   [1913 Webster]

WordNet (r) 3.0 (2006):

hectometer
    n 1: a metric unit of length equal to 100 meters [syn:
         hectometer, hectometre, hm]