Source : Webster's Revised Unabridged Dictionary (1913)

Mensuration \Men`su*ra"tion\, n. [L. mensuratio : cf. F.
   mensuration.]
   1. The act, process, or art, of measuring.

   2. That branch of applied geometry which gives rules for
      finding the length of lines, the areas of surfaces, or the
      volumes of solids, from certain simple data of lines and
      angles.

Source : WordNet®

mensuration
     n : the act or process of measuring; "the measurements were
         carefully done"; "his mental measurings proved remarkably
         accurate" [syn: {measurement}, {measuring}, {measure}]