[ bahy-muhnth-lee ]
/ baɪˈmʌnθ li /
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occurring every two months.
occurring twice a month; semimonthly.
noun, plural bi·month·lies.
a bimonthly publication.
every two months: Next year we plan six field trips to take place bimonthly.
twice a month; semimonthly.
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Origin of bimonthly

First recorded in 1840–50; bi-1 + monthly

words often confused with bimonthly

See bi-1.


bimonthly , biweekly, semimonthly (see confusables note at bi-1)
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023


What does bimonthly mean?

Bimonthly is commonly used to mean one of two things: once every two months or twice per month.

It can be used this way as an adjective, as in a bimonthly meeting, or an adverb, as in We plan to meet bimonthly. 

Yes, you can sometimes figure out what bimonthly means from the context of the sentence. But not always. The term bimonthly meeting might mean that it happens twice a month or every two months—both senses of the word are commonly used. Here’s the best (and maybe only) way to be perfectly clear: just say “twice a month” or “once every two months.”

Bimonthly can also be used as a noun referring to a publication that’s published twice per month or once every two month (as opposed to a daily or weekly, for example).


  • New episodes of my bimonthly podcast come out on the first and 15th of every month. 
  • Let’s plan to meet bimonthly so we can fit in six meetings this year.

Where does bimonthly come from?

The first records of the word bimonthly come from the 1800s. The prefix bi- means “twice” or “two.” The suffix -ly, which usually forms adverbs, is used in bimonthly to mean “every.” It’s used in the same way in several other units of time, including hourly, daily, monthly, and yearly.

Different prefixes can be added to monthly to indicate a different period of time, such as in trimonthly (every three months or three times a month) and semimonthly (twice a month). When intended to mean “twice a month,” bimonthly is sometimes replaced with semimonthly for clarity, but this might not help, especially since semimonthly is much less common. Further confusing things is the fact that bimonthly can essentially mean biweekly—“every two weeks.” But biweekly can also mean “twice a week.” The easiest thing to do is just say exactly when the meetings will be—or cancel them all together.

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What are some other forms related to bimonthly?

  • bimonthlies (plural noun)

What are some synonyms for bimonthly?

What are some words that share a root or word element with bimonthly


What are some words that often get used in discussing bimonthly?

How is bimonthly used in real life?

Bimonthly is commonly used to mean both “twice a month” and “every two months.” To avoid confusion, it’s a good idea to clarify exactly which one you mean.



Try using bimonthly!

Is bimonthly used correctly in the following sentence?

The magazine will transition from being a bimonthly to a quarterly.

How to use bimonthly in a sentence

British Dictionary definitions for bimonthly

/ (baɪˈmʌnθlɪ) /

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
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012