Biennial: - Issued every two years. Also refers to a serial publication issued
every two years.
Semiannual: - Issued at intervals of six months. Also refers to a
serial issued every six months. Synonymous with half yearly and twice yearly.
Annual: - Issued once a year, every year, as in an annual
report or annual review.
Triennial: - Issued every three years. Also refers to a serial
publication issued every three years.
Quadrennial: - Issued every four years. Also refers to a serial
publication issued every four years.
Quinquennial:- Issued very five years. Also refers to a serial publication
issued every five years (example: Biography and Genealogy Master Index).
Sexennial: - Issued every six years. Also refers to a serial publication issued
every six years.
Septennial: - Issued every seven years. Also refers to a serial publication
issued every seven years.
Decennial: - Issued every 10 years (example: U.S. Census). Also refers to a
serial publication issued every 10 years.
