Bi-annually is a term used to describe something that occurs twice a year. There are several synonyms for this word that can be used interchangeably, depending on the context. Semi-annually is one synonym that is commonly used in business to describe events or reports that are generated every six months. Another synonym is biennially, which can be used to describe events that occur every two years. If the frequency of the event is not as rigid, you can use the phrase "twice a year" or "every six months". These synonyms are helpful when trying to communicate the frequency of events without using the same word repeatedly.