What does bimester mean?
A bimester is a period of two months, formed on the same Latin pattern as its better-known cousins the semester (six months) and the trimester (three months). The word derives from the Latin prefix bi-, meaning 'two', combined with mensis, meaning 'month'. Though it never achieved the everyday currency of those relatives, the bimester fills a genuine gap in the vocabulary of timekeeping: it names precisely the eight-to-nine-week span that falls between 'a couple of months' and a quarter. In practice it appears most often in formal contexts such as academic calendars, payment schedules, publication cycles, and administrative planning, where activities are divided into regular two-month terms. The related adjective 'bimestrial' describes something occurring every two months or lasting two months, and this form is arguably encountered slightly more often than the noun. Writers seeking an exact, economical alternative to the vague phrase 'every two months' will find the bimestrial family a useful, if uncommon, resource.
nounA period of two months.
- A period or term of two months, especially as a unit of time in scheduling, publication, or academic planning.
"The fellowship is paid in three installments, one per bimester."
"The magazine moved from quarterly to bimester publication to keep coverage more current."
"Students take an intensive language module each bimester throughout the program."
Standard plural, used when referring to multiple discrete two-month periods.
"The course runs across four bimesters, with examinations after each."
While everyone knows the semester and the trimester, the humble two-month stretch has its own name too — the bimester, straight from the Roman mensis for 'month'.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of bimester
Bimester comes from Latin, combining the prefix bi- ('twice' or 'two') with mensis ('month'); the Latin adjective bimensis meant 'lasting two months' or 'occurring every second month'. English adopted it by analogy with the earlier borrowings semester (from German, ultimately Latin semenstris, 'half-yearly') and trimester, which established the pattern of '-mester/-mester' terms for multi-month periods. Its cognates include trimester, semester, and other mensis-derived words such as menstrual and menology.
Related word forms
How bimester is actually used
A relatively rare, formal word used chiefly in academic, administrative, and publishing contexts where precise two-month divisions matter. The adjective form 'bimestrial' (relating to or occurring every two months) is somewhat more common than the noun itself.
Easily confused with bimester
A trimester is a period of three months, while a bimester is a period of two months.
A semester is a half-year academic term of about six months, whereas a bimester spans only two months.