Source : Webster's Revised Unabridged Dictionary (1913)

Decimeter \Dec"i*me`ter\, Decimetre \Dec"i*me`tre\, n. [F.
   d['e]cim[`e]tre; pref. d['e]ci- tenth (fr. L. decimus) +
   m[`e]tre. See {Meter}.]
   A measure of length in the metric system; one tenth of a
   meter, equal to 3.937 inches.

Source : WordNet®

decimetre
     n : a metric unit of length equal to one tenth of a meter [syn:
         {decimeter}, {dm}]