'Septuagesimal' definitions:

Definition of 'Septuagesimal'

From: GCIDE

Septuagesimal \Sep`tu*a*ges"i*mal\, a. Consisting of seventy days, years, etc.; reckoned by seventies. [1913 Webster]
Our abridged and septuagesimal age. --Sir T. Browne. [1913 Webster]