The Collaborative International Dictionary of English v.0.48:

Separatrix \Sep`a*ra"trix\, n.; pl. L. -trices, E. -trixes.
   [L., she that separates.] (Arith.)
   The decimal point; the dot placed at the left of a decimal
   fraction, to separate it from the whole number which it
   follows. The term is sometimes also applied to other marks of
   separation.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Impropriatrix \Im*pro`pri*a"trix\, n.; pl. E. -trixes, L.
   -trices.
   A female impropriator.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Quadratrix \Quad*ra"trix\, n.; pl. -trixes, or -trices.
   [NL.] (Geom.)
   A curve made use of in the quadrature of other curves; as the
   quadratrix, of Dinostratus, or of Tschirnhausen.
   [1913 Webster]