Bimonthly may mean occurring twice a month or occurring every two months. Bimonthly may be used as an adjective or an adverb. In the United States bimonthly may be used as a noun to describe periodicals, the plural noun form is bimonthlies. Bimonthly is derived from the prefix bi-, which means two, twice, double, doubly, occurring twice in every one or once in every two. It comes from the Latin bi-, meaning twice, double, and weekly from the Old English word monað.
Semimonthly means occurring twice a month. Semimonthly is an adjective that is derived from the prefix semi-, which means half, part, partly, twice, as it comes from the Latin semi-, meaning half, and monthly. In the United States semimonthly may be used as a noun, the plural noun form is semimonthlies. Semimonthly is often found hyphenated as in semi-monthly, but the Oxford English dictionary only lists it as one word, unhyphenated. Remember, bimonthly may mean occurring twice a month or occurring every two months, semimonthly only means occurring twice a month.
Examples
The new bimonthly report on Cyprus to the Congress, by President Barack Obama, focuses on the historic visit to the island paid by Secretary of State John Kerry last December and on the meetings Vice President Biden had regarding Cyprus, on the sidelines of the Davos World Economic Forum as well as in Turkey. (Famagusta Gazette)
The Citizens Advisory Board, or CAB, held its bimonthly meeting Monday and Tuesday to discuss nuclear materials, environmental hazards and to vote on recommendations to Savannah River Site, or SRS, nuclear entities. (The Aiken Standard)
That’s why the gruesome twosome started their Die Felicia series – a semimonthly night that incorporates classic horror films, drag, and trivia in one safe space for horror fans. (The Austin Chronicle)
Riddle said that periodically, there are 27 semi-monthly pay periods for county employees because of the way the calendar falls, and next fiscal year will be one of them, so the budget is going to appear as if salaries and benefits were increased significantly, when that’s really not the case, per se. (The Glasgow Daily Times)