The Collaborative International Dictionary of English v.0.48:

Sextile \Sex"tile\, a. [F. sextil, fr. L. sextus the sixth, from
   sex six. See Six.] (Astrol.)
   Measured by sixty degrees; fixed or indicated by a distance
   of sixty degrees. --Glanvill.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sextile \Sex"tile\, n. [Cf. F. aspect sextil.] (Astrol.)
   The aspect or position of two planets when distant from each
   other sixty degrees, or two signs. This position is marked
   thus: ********. --Hutton.
   [1913 Webster]