- quadrennial (adj.)
[quadrennial 词源字典]
- 1650s, "lasting four years;" as "happening once every four years," 1701; from quadri- + ending from biennial, etc. Correct formation would be quadriennial (compare Latin quadriennium "period of four years"). As a noun from 1640s. Related: Quadrennially.[quadrennial etymology, quadrennial origin, 英语词源]