Biannual, Biennial, Semiannual
These words do not all mean the same thing. Biannual means "twice a year," as does semiannual, whereas biennial means "occurring every two years."
Confusing Words and Homonyms
Letter A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z