Source : Webster's Revised Unabridged Dictionary (1913)

Half-length \Half"-length`\, a.
   Of half the whole or ordinary length, as a picture.

Source : WordNet®

half-length
     adj 1: representing only the upper half of the body; "a half-length
            portrait"
     2: abridged to half its original length
     n : a portrait showing the body from only the waist up