What is the meaning of Quinquennial?

Of or related to a five-year period.

Synonym of quinquennium, a five-year period.

A 5th anniversary, particularly

  1. Synonym of quinquennalia, the festival and religious ritual held in the 5th year of a Roman emperor's reign.

Synonym of quinquennalia, the festival and religious ritual held in the 5th year of a Roman emperor's reign.

Source: wiktionary.org