- quinquennial (adj.)
[quinquennial 词源字典]
- late 15c., "lasting five years," from Latin quinquennis "of five years, celebrated every fifth year," from quinque- "five" (see quinque-) + ending from biennial, etc. Meaning "happening once every five years" attested from c. 1600. As a noun from 1895; earlier quinquennal (1610s).[quinquennial etymology, quinquennial origin, 英语词源]