duodecade
A period of twelve years.
Each Chinese New Year during a "Jupiter return"—when a duodecade has passed and the Chinese zodiac animal of your birth year comes back around—it is expected that you find some red underwear to put on for the special occasion.
Where it comes from
Borrowed from Late Latin duodecas (“twelve”), from Ancient Greek δυωδεκάς (duōdekás, “twelve”). Equivalent to duodec- + -ade.
Adapted from the Wiktionary entry duodecade (CC BY-SA 4.0).