sexagenary

From French sexagénaire, from Latin sexāgēnārius (“the adjectival form of sixty; sixty years old; a sixty-year-old”)

sexagenary (not comparable)

1. Of or related to the number sixty, particularly:
   1. Containing sixty years.

      The sexagenary cycle is formed by combining the twelve earthly branches representing the years of Jupiter's orbital cycle and the ten heavenly stems of the Shang-era week, stopping halfway through to reflect the pairing of yin and yang terms.

   2. (now rare) Synonym of sexagenarian: lasting or aged sixty years; sixty-year-old.
   3. (mathematics, astronomy, now rare) Synonym of sexagesimal: base-60.

sexagenary (plural sexagenaries)

1. (mathematics, astronomy, now rare) Synonym of sexagesimal: base-60 numeration.
2. (now rare) Synonym of sexagenarian: a sixty-year-old.