The Collaborative International Dictionary of English v.0.48:

Sexagesimal \Sex`a*ges"i*mal\, a. [Cf. F. sexag['e]simal.]
   Pertaining to, or founded on, the number sixty.
   [1913 Webster]

   Sexagesimal fractions or Sexagesimal numbers (Arith. &
      Alg.), those fractions whose denominators are some power
      of sixty; as, 1/60, 1/3600, 1/216000; -- called also
      astronomical fractions, because formerly there were no
      others used in astronomical calculations.

   Sexagesimal arithmetic, or Sexagenary arithmetic, the
      method of computing by the sexagenary scale, or by
      sixties.

   Sexagesimal scale (Math.), the sexagenary scale.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sexagenary \Sex*ag"e*na*ry\, a. [L. sexagenarius, fr. sexageni
   sixty each, akin to sexaginta sixty, sex six: cf.
   sexag['e]naire. See Six.]
   Pertaining to, or designating, the number sixty; poceeding by
   sixties; sixty years old.
   [1913 Webster]

   Sexagenary arithmetic. See under Sexagesimal.

   Sexagenary scale, or Sexagesimal scale (Math.), a scale
      of numbers in which the modulus is sixty. It is used in
      treating the divisions of the circle.
      [1913 Webster]