from The American Heritage® Dictionary of the English Language, 4th Edition

  • Two: biform.
  • Both: binaural.
  • Both sides, parts, or directions: biconcave.
  • Occurring at intervals of two: bicentennial.
  • Usage Problem Occurring twice during: biweekly.
  • Containing twice the proportion of a specified chemical element or group necessary for stability: bicarbonate.
  • Containing two chemical atoms, radicals, or groups: biphenyl.
  • Variant of bio-.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • two
  • half

from the GNU version of the Collaborative International Dictionary of English

  • In most branches of science bi- in composition denotes two, twice, or doubly
  • In the composition of chemical names bi- denotes two atoms, parts, or equivalents of that constituent to the name of which it is prefixed, to one of the other component, or that such constituent is present in double the ordinary proportion. Be- and di- are often used interchangeably.

from The Century Dictionary and Cyclopedia

  • A common Middle English form of the preposition by.
  • The chemical symbol of bismuth.
  • A Middle English and Anglo-Saxon form of be- or be-.
  • A prefix of Latin origin, cognate with di- and twi-, meaning two, two-, twice, double, twofold, as in biaxial, bicornous, bimanous, biped, bifurcate, etc.: especially in chemical terms, where it denotes two parts or equivalents of the ingredient referred to, as in bicarbonate, bichromate, etc.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. a heavy brittle diamagnetic trivalent metallic element (resembles arsenic and antimony chemically); usually recovered as a by-product from ores of other metals


Latin bis, bi-, twice, and bīnī, two by two; see dwo- in Indo-European roots.
(American Heritage® Dictionary of the English Language, Fourth Edition)
From Latin bis ("twice"). (Wiktionary)


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  • He wiggled his fingers, occasionally bent forward to stretch out his calves and thighs, or reached overhead with one hand to touch the other shoulder, stretching bi- and triceps.

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  • The visible result of this phenomenon is the bulge of the bi- and triceps when we flex our muscles.


  • A multigoal and conflict-acknowledging model of the firm is more compatible with the bi- or multiple utility conception and the I&We paradigm.


  • Although the agency didn't mention any risks to its bond rating in its statement, Governors Andrew Cuomo of New York and Chris Christie of New Jersey, who share oversight of the bi- state agency, released a joint statement in which they said agency officials may have such worries. -- Top News

  • Last month, Najib said the government would establish a bi- partisan parliamentary committee to review changes to electoral rules, and that authorities would also consider amending laws governing censorship of print media. -- Top News

  • Even if sexual orientation were a choice, aren’t we a country where we’re supposed to be free to pursue our happiness, whether we’re hetero-, homo-, bi-, trans-, or even a-sexual?

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  • this is one of the more coherent and consistent of the multitude of bi- and triennial exhibitions cropping up across the world.

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