Source : Webster's Revised Unabridged Dictionary (1913)

Sesquiplicate \Ses*quip"li*cate\, a. [Sesqui- + plicate.]
   (Math.)
   Subduplicate of the triplicate; -- a term applied to ratios;
   thus, a and a' are in the sesquiplicate ratio of b and b',
   when a is to a' as the square root of the cube of b is to the
   square root of the cube of b', or
   a:a'::[root]b^{3}:[root]b'^{3}.

         The periodic times of the planets are in the
         sesquiplicate ratio of their mean distances. --Sir I.
                                                  Newton.