PREFIX
bi- two
cent- hundred
per- through
uni- one

ROOT
enni year
later side

SUFFIX
-al like, related to

WORDS AND DEFINITIONS
bicentennial - of or relating to an age or period of 200 years
centennial - of or relating to an age or period of 100 years
perennial - lasting through many years
bilateral - of or involving two sides; reciprocal
unilateral - affecting one side of something