What is the word for something that occurs every two months?

From the Related Link below: ; bimonthly / semimonthly : Bimonthly is an adjective that means every two months: "I brought the cake for the bimonthly office party." Bimonthlyis also a noun that means a publication issued every two months: "The company publishes several popular bimonthlies." Semimonthly is an adjective that means happening twice a month: "We have semimonthly meetings on the 1st and the 15th."