senary

/S EH1 N ER0 IY0/
noun
  1. 1

    The numeral system which uses six as the base.

adjective
  1. 1

    Of sixth rank or order.

  2. 2

    Of, pertaining to, or based on six.

    โ€œThe senary fraction 0.2 is one-third, i.e. two-sixths.โ€

Source: https://en.wiktionary.org/wiki/senary