প্রত্যেক 20 বছর একবার ঘটছে

Adjective:

কুড়ি বছর স্থায়ী,

vicennial's Usage Examples:

summarized developments to the propaganda model on the occasion of the vicennial anniversary of first publication of Manufacturing Consent.

For comparison, the June 1963 value is comparable to a vicennial flood event, and is thus considered not that exceptional.

Sabathia was one of the most dominant pitchers in the vicennial (twenty year) period of 2000 to 2020; posting more wins, games started.

elections of December 1937, upon the end of Greater Romania's liberal vicennial.

recognition of a quarter century spent as an active duty soldier, and almost vicennial record of his service with the ROTC.

vicennial's Meaning':

occurring once every 20 years