1. Characterized by or consisting of two parts or components; twofold.
a. Of or relating to a system of numeration having 2 as its base.
b. Of or relating to a system of encoding data using only 0's and 1's.
3. Chemistry Consisting of or containing only two kinds of atoms.
4. Of or employing two comparatively nontoxic chemicals that combine to produce a deadly poison: binary weapons; a binary nerve agent.
5. Music Having two sections or subjects.
n. pl. bi·na·ries
1. A number system having 2 as its base.
2. A file that contains the executable version of a computer program.
3. A binary star.
[Middle English binarie, from Late Latin bīnārius, from Latin bīnī, two by two; see dwo- in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2017 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The American Heritage Dictionary Blog
Check out our blog, updated regularly, for new words and revised definitions, interesting images from the 5th edition, discussions of usage, and more.
American Heritage Dictionary Products
The American Heritage Dictionary, 5th Edition
The American Heritage Dictionary of Idioms
The American Heritage Roget's Thesaurus
Curious George's Dictionary
The American Heritage Children's Dictionary
The American Heritage Dictionary of Indo-European Roots
The American Heritage Student Grammar Dictionary
The American Heritage Desk Dictionary + Thesaurus
The American Heritage Science Dictionary
The American Heritage Dictionary of Business Terms
The American Heritage Student Dictionary
The American Heritage Essential Student Thesaurus