— bicentennially , adv.
/buy'sen ten"ee euhl/ , adj.
1. pertaining to or in honor of a 200th anniversary: bicentennial celebration; a bicentennial exposition.
2. consisting of or lasting 200 years: a bicentennial period.
3. occurring every 200 years: the bicentennial return of a comet.
n.
4. a 200th anniversary: The United States had its bicentennial in 1976.
5. a celebration of such an anniversary.
Also, esp. Brit., bicentenary .
[ 1880-85; BI- 1 + CENTENNIAL ]
Usage . See bi- 1 .