duodecennial

adjective2

1. •
   Consisting of twelve years, occurring in 12-year cycles.

   • The duodecennial Chinese zodiac originated from Chinese and Indian observations of the duodecennial cycle of the Jovian orbit.
2. •
   Occurring once a duodecade, occurring every 12 years.

   • The concept of a duodecennial "Jupiter return" in Western astrology arose from similar concerns.