bi

1 of 4

noun or adjective

ˈbī 

: bisexual

bi-

2 of 4

prefix

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- sense 2

biphenyl

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.

bi-

3 of 4

combining form

variants or bio-

1

: life : living organisms or tissue

bioluminescence

biosphere

2

: biographical

biopic

Bi

4 of 4

symbol

bismuth

Word History

Etymology

Prefix

Middle English, from Latin — more at twi-

Combining form

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

First Known Use

Noun Or Adjective

1956, in the meaning defined above

Phrases Containing bi

• bi-gender
• bi-swing

Kids Definition

bi-

combining form

1

: two

bipartisan

2

: coming or occurring every two

bimonthly

3

: into two parts

bisect

Etymology

Combining form

derived from Latin bi- (prefix) "two"

Medical Definition

Bi

symbol

bismuth