adjective
- occurring every two months.
- occurring twice a month; semimonthly.
noun, plural bi·month·lies.
- a bimonthly publication.
adverb
- every two months: Next year we plan six field trips to take place bimonthly.
- twice a month; semimonthly.
adjective, adverb
- every two months
- (often avoided because of confusion with sense 1) twice a month; semimonthlySee bi- 1
noun plural -lies
- a periodical published every two months
also bi-monthly, 1846, “happening once in two months, every two months,” also “occurring twice a month,” a hybrid from bi- + monthly.