When an event, phenomenon, or occurrence happens twice a year, it can be described using various synonyms. For example, the phrase "biannual" is a common term used to describe events that occur twice a year. Another synonym for "biannual" is "biyearly." Alternatively, "semiannual" is another term used to describe events that happen twice a year. This word can be further simplified to "half-yearly" or "twice-yearly." Additionally, the phrase "biannual occurrence" can be replaced with "biennial," which specifically refers to events that happen once every two years. Understanding the various synonyms for "occurring twice a year" can help to communicate more effectively and accurately.