\ ˈbī How to pronounce bi (audio) \

Definition of bi

 (Entry 1 of 4)



Definition of bi- (Entry 2 of 4)

1a : two bilateral
b : coming or occurring every two bicentennial
c : into two parts bisect
2a : twice : doubly : on both sides biconvex
b : coming or occurring two times biannual — compare semi-
3 : between, involving, or affecting two (specified) symmetrical parts bilabial
4a : containing one (specified) constituent in double the proportion of the other constituent or in double the ordinary proportion bicarbonate
b : di- sense 2 biphenyl
variants: or bio-

Definition of bi- (Entry 3 of 4)

1 : life : living organisms or tissue bioluminescence biosphere
2 : biographical biopic

Definition of Bi (Entry 4 of 4)


What do bimonthly and biweekly mean?: Usage Guide


Many people are puzzled about bimonthly and biweekly, which are often ambiguous because they are formed from two different senses of bi-: "occurring every two" and "occurring two times." This ambiguity has been in existence for nearly a century and a half and cannot be eliminated by the dictionary. The chief difficulty is that many users of these words assume that others know exactly what they mean, and they do not bother to make their context clear. So if you need bimonthly or biweekly, you should leave some clues in your context to the sense of bi- you mean. And if you need the meaning "twice a," you can substitute semi- for bi-. Biannual and biennial are usually differentiated.

First Known Use of bi

Noun or adjective

1956, in the meaning defined above

History and Etymology for bi


Middle English, from Latin — more at twi-

Combining form

Greek, from bios mode of life — more at quick entry 1

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Cite this Entry

“Bi.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/bi. Accessed 1 Oct. 2020.

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More Definitions for bi



English Language Learners Definition of bi-

: two
: coming or happening every two
: coming or happening two times



Kids Definition of bi-

1 : two biped
2 : coming or occurring every two biennial
3 : into two parts bisect
4 : twice : doubly : on both sides

Medical Definition of Bi


More from Merriam-Webster on bi

Britannica.com: Encyclopedia article about bi

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