ship images. The Makin Island Raid (occurred on 17 - 18 August 1942) was an attack by the United States Marine Corps on Japanese military forces on Makin Island (now known as Butaritari Island) in the Pacific Ocean.
Biannual is derived from the prefix bi-, which means two, twice, double, doubly, as it comes from the Latin bi-, meaning twice, double, and annual comes from the Old French twelfth century word, annuel, which derives from the Latin annus, year.
Confidence votes 7.7K. There is disagreement on whether there even exists a proper, unambiguous term for every four months.. Many use triannual for the purpose. There is some logic to this, since biannual means twice yearly, whereas biennial means every two years, and triennial means every three years.