bi·an·nu·al 
/baɪˈænjəwəl/ adjective
always used before a noun /baɪˈænjəwəl/ adjective 1 : happening twice a year : semiannual
▪ The group holds biannual meetings in December and July. 2 : happening every two years : biennial
▪ The art show is a biannual event that won't happen again for two more years.
▪ The group holds biannual meetings in December and July.
▪ The art show is a biannual event that won't happen again for two more years.
— bi·an·nu·al·ly adverb
