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: Webster's Revised Unabridged Dictionary (1913)