bi

noun or adjective \ ˈbī \
Updated on: 14 Nov 2017

Definition of bi

Recent Examples of bi from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'bi.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of bi

1956


1

bi-

prefix

Definition of bi-

1 a : two
  • bilateral
b : coming or occurring every two
  • bicentennial
c : into two parts
  • bisect
2 a : 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
4 a : containing one (specified) constituent in double the proportion of the other constituent or in double the ordinary proportion
  • bicarbonate
b : di- 2
  • biphenyl

What do bimonthly and biweekly mean?

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.


Origin and Etymology of bi-

Middle English, from Latin — more at twi-


2

bi-

combining form
variants: or bio-

Definition of bi-

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

Origin and Etymology of bi-

Greek, from bios mode of life — more at quick


Bi

symbol

Definition of Bi

bismuth

Other Chemical Engineering Terms


BI Defined for English Language Learners

bi-

prefix

Definition of bi- for English Language Learners

  • : two

  • : coming or happening every two

  • : coming or happening two times


BI Defined for Kids

bi-

prefix

Definition of bi- for Students

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

Medical Dictionary

Bi

symbol

medical Definition of Bi

bismuth

Learn More about bi


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