adjective, noun, plural bis, bi's.
Slang. bisexual.

by shortening Unabridged


plural BI's. built-in.


Symbol, Chemistry.


a combining form meaning “twice,” “two,” used in the formation of compound words: bifacial; bifarious.
Compare bin-.

< Latin, combining form of bis; see twice

All words except biennial referring to periods of time and prefixed by bi-1 are potentially ambiguous. Since bi- can be taken to mean either “twice each” or “every two,” a word like biweekly can be understood as “twice each week” or “every two weeks.” To avoid confusion, it is better to use the prefix semi- to mean “twice each” (semiannual; semimonthly; semiweekly) or the phrase twice a or twice each (twice a month; twice a week; twice each year), and for the other sense to use the phrase every two (every two months; every two weeks; every two years).


variant of bio-, especially before a vowel: biopsy. Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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World English Dictionary
bi1 (baɪ)
adj, —n
slang bisexual short for bisexual

the internet domain name for

the chemical symbol for

bi- or (sometimes before a vowel) bin-1
combining form
1.  two; having two: bifocal
2.  occurring every two; lasting for two: biennial
3.  on both sides, surfaces, directions, etc: bilateral
4.  occurring twice during: biweekly
5.  a.  denoting an organic compound containing two identical cyclic hydrocarbon systems: biphenyl
 b.  (rare in technical usage) indicating an acid salt of a dibasic acid: sodium bicarbonate
 c.  (not in technical usage) equivalent of di-
[from Latin, from bistwice]
bin- or (sometimes before a vowel) bin-1
combining form
[from Latin, from bistwice]

combining form
a variant of bio-

Collins English Dictionary - Complete & Unabridged 10th Edition
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Main Entry:  BI
Part of Speech:  n
Definition:  See business intelligence's 21st Century Lexicon
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Word Origin & History

prefix meaning "two, twice, double," etc., from L. bi-, from Old L. dvi- (cognate of Skt. dvi-, Gk. di-, O.E. twi-), from PIE base *dwo- "two." Nativized from 16c.

1956, colloquial abbreviation of bisexual (see bisexuality).
Online Etymology Dictionary, © 2010 Douglas Harper
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American Heritage
Medical Dictionary

The symbol for the element bismuth.

bi- 1 or bin-

  1. Two: bilateral.

  2. Both: binaural.

  3. Both sides, parts, or directions: biconcave.

  4. Containing twice the proportion of a specified chemical element or group necessary for stability: bicarbonate.

  5. Containing two chemical atoms, radicals, or groups: biphenyl.

bi- 2
Variant of bio-.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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American Heritage
Science Dictionary
The symbol for bismuth.
bismuth   (bĭz'məth)  Pronunciation Key 
Symbol Bi
A brittle, pinkish-white, crystalline metallic element that occurs in nature as a free metal and in various ores. Bismuth is the most strongly diamagnetic element and has the highest atomic number of all stable elements. It is used to make low-melting alloys for fire-safety devices. Atomic number 83; atomic weight 208.98; melting point 271.3°C; boiling point 1,560°C; specific gravity 9.747; valence 3, 5. See Periodic Table.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Computing Dictionary

bi definition

The country code for Burundi.

The Free On-line Dictionary of Computing, © Denis Howe 2010
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American Heritage
Abbreviations & Acronyms
  1. bisexual

  2. bismuth

  1. background information

  2. bodily injury

  3. built-in

The American Heritage® Abbreviations Dictionary, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Encyclopedia Britannica


in art, Chinese jade carved in the form of a flat disk with a hole in the centre. The earliest examples, which are unornamented, date from the Neolithic Period (c. 5000-2000 BC). Later examples, from the Shang (18th-12th century BC) and Zhou dynasties (1111-256/255 BC), have increasingly elaborate surface embellishment, especially in the late Zhou (c. 600-256/255 BC), when the bi appeared in combination with other forms

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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