semiannual

Semiannual is an adjective meaning occurring twice within a year, roughly every six months. The term derives from Latin semi- meaning half and annus meaning year. The adverb form is semiannually. Many style guides prefer semiannual over biannual due to potential ambiguity, since biannual can be read as either twice a year or once every two years depending on context; semiannual clearly indicates twice yearly.

Usage is common in finance, business, law, and project planning. It describes payments or events that happen twice a year, such as semiannual interest on bonds, semiannual dividends, or the issuance of a semiannual financial report. Contracts may specify semiannual renewals or audits.

Examples include a bond that pays semiannual interest on January 1 and July 1, or a company that publishes a semiannual report covering the first half of the year.

Relation to related terms: Biennial means once every two years; biannual is variably used and can be ambiguous. When precision is required, it is clearer to say "twice a year" or give explicit dates rather than relying on the term.

Notes: In calendar practice, the exact six-month interval depends on the starting point, since calendar months vary in length; thus, semiannual implies a six-month interval, but the number of days between events can differ.

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