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[bahy-nuh-ree, -ner-ee] /ˈbaɪ nə ri, -nɛr i/
consisting of, indicating, or involving two.
  1. of or relating to a system of numerical notation to the base 2, in which each place of a number, expressed as 0 or 1, corresponds to a power of 2. The decimal number 58 appears as 111010 in binary notation, since 58 = 1 × 2 5 + 1 × 2 4 + 1 × 2 3 + 0 × 2 2 + 1 × 2 1 + 0 × 2 0 .
  2. of or relating to the digits or numbers used in binary notation.
  3. of or relating to a binary system.
  4. (of an operation) assigning a third quantity to two given quantities, as in the addition of two numbers.
Computers. of, relating to, or written in binary code; programmed or encoded using only the digits 0 and 1:
All executable programs on the computer are stored in binary files.
Chemistry. noting a compound containing only two elements or groups, as sodium chloride, methyl bromide, or methyl hydroxide.
Metallurgy. (of an alloy) having two principal constituents.
noun, plural binaries.
a whole composed of two.
Mathematics. a system of numerical notation to the base 2, in which each place of a number, expressed as 0 or 1, corresponds to a power of 2:
to convert decimal to binary.
Also called binary number. Mathematics. a number expressed in the binary system of notation.
Computers. binary code.
Computers. an executable file stored in binary format.
Astronomy. binary star.
Origin of binary
1350-1400; Middle English < Late Latin bīnārius, equivalent to bīn(ī) (see bin-) + -ārius -ary
Can be confused
binary, bindery. Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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Examples from the Web for binary
Contemporary Examples
Historical Examples
  • Each pair is apparently a binary; but the period of revolution is unknown.

    Pleasures of the telescope Garrett Serviss
  • It is regarded as a binary of long and as yet unascertained period.

    Pleasures of the telescope Garrett Serviss
  • Antares is probably a binary, although its binary character has not yet been established.

    Pleasures of the telescope Garrett Serviss
  • It is only in the case of binary systems that we can discover the masses of stars at all.

    Astronomy of To-day Cecil G. Dolmage
  • The binary coloured systems are not all composed of blue and red suns.

    Everyday Objects W. H. Davenport Adams
British Dictionary definitions for binary


composed of, relating to, or involving two; dual
(maths, computing) of, relating to, or expressed in binary notation or binary code
(of a compound or molecule) containing atoms of two different elements
(metallurgy) (of an alloy) consisting of two components or phases
(of an educational system) consisting of two parallel forms of education such as the grammar school and the secondary modern in Britain
(maths, logic) (of a relation, expression, or operation) applying to two elements of its domain; having two argument places; dyadic
noun (pl) -ries
something composed of two parts or things
(astronomy) See binary star
short for binary weapon
Word Origin
C16: from Late Latin bīnārius; see bin-
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for binary

"dual," mid-15c., from Late Latin binarius "consisting of two," from bini "twofold, two apiece, two-by-two" (used especially of matched things), from bis "double" (see bis-). Binary code in computer terminology was in use by 1952, though the idea itself is ancient. Binary star in astronomy is from 1802.

Online Etymology Dictionary, © 2010 Douglas Harper
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binary in Medicine

binary bi·na·ry (bī'nə-rē)

  1. Characterized by or consisting of two parts or components; twofold.

  2. Consisting of or containing only molecules having two kinds of atoms.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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binary in Science
  1. Having two parts.

  2. Mathematics Based on the number 2 or the binary number system.

The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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binary in Culture
binary [(beye-nuh-ree, beye-ner-ee)]

Anything composed of two parts. In modern computers, information is stored in banks of components that act like switches. Since switches can be either on or off, they have a binary character, and we say that the computer uses “binary arithmetic” to do its work.

The New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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