The Collaborative International Dictionary of English v.0.48:

Sextans \Sex"tans\, n. [L. See Sextant.]
   1. (Rom. Antiq.) A Roman coin, the sixth part of an as.
      [1913 Webster]

   2. (Astron.) A constellation on the equator south of Leo; the
      Sextant.
      [1913 Webster]