Source : Webster's Revised Unabridged Dictionary (1913)

Isometric \I`so*met"ric\, Isometrical \I`so*met"ric*al\, a.
   [Iso- + Gr. ? measure.]
   1. Pertaining to, or characterized by, equality of measure.

   2. (Crystallog.) Noting, or conforming to, that system of
      crystallization in which the three axes are of equal
      length and at right angles to each other; monometric;
      regular; cubic. Cf. {Crystallization}.

   {Isometric lines} (Thermodynamics), lines representing in a
      diagram the relations of pressure and temperature in a
      gas, when the volume remains constant.

   {Isometrical perspective}. See under {Perspective}.

   {Isometrical projection}, a species of orthographic
      projection, in which but a single plane of projection is
      used. It is so named from the fact that the projections of
      three equal lines, parallel respectively to three
      rectangular axes, are equal to one another. This kind of
      projection is principally used in delineating buildings or
      machinery, in which the principal lines are parallel to
      three rectangular axes, and the principal planes are
      parallel to three rectangular planes passing through the
      three axes.