binary

American  

[bahy-nuh-ree, -ner-ee] / ˈbaɪ nə ri, -nɛr i /

adjective

1. consisting of, indicating, or involving two.

2. Mathematics.

   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.

3. 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.

4. Chemistry. noting a compound containing only two elements or groups, as sodium chloride, methyl bromide, or methyl hydroxide.

5. Metallurgy. (of an alloy) having two principal constituents.

---

noun

plural

binaries

1. a whole composed of two.

2. 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.

3. Also called binary number.  Mathematics. a number expressed in the binary system of notation.

4. Computers. binary code.

5. Computers. an executable file stored in binary format.

6. Astronomy. binary star.

binary British  

/ ˈbaɪnərɪ /

adjective

1. composed of, relating to, or involving two; dual

2. maths computing of, relating to, or expressed in binary notation or binary code

3. (of a compound or molecule) containing atoms of two different elements

4. metallurgy (of an alloy) consisting of two components or phases

5. (of an educational system) consisting of two parallel forms of education such as the grammar school and the secondary modern in Britain

6. maths logic (of a relation, expression, or operation) applying to two elements of its domain; having two argument places; dyadic

---

noun

1. something composed of two parts or things

2. astronomy See binary star

3. short for binary weapon

binary Scientific  

/ bī′nə-rē /

1. Having two parts.

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

---

binary Cultural  

1. 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.

---

Etymology

Origin of binary

First recorded in 1350–1400; Middle English, from Late Latin bīnārius, equivalent to bīn(ī) ( bin- ) + -ārius -ary

Explanation

Something that can be broken into two categories is binary. Binary means something close to dual or double. You can remember what binary means if you know that bi- means two. Black and white are often set up as a binary, as are light and dark and good and evil. One binary we see all the time is the male and female symbols you see on bathroom doors. In computing, binary is a code of zeros and ones (computer programming) also known as base two. A binary is also a double star — two stars revolving around each other.

Example Sentences

“He really looked at the world, not through any kind of binary lens, but through a personal lens that was respectful of other people’s perspective.”

From Los Angeles Times • Apr. 3, 2026

"It's not a binary on/off effect; it can be a scaled response, like a dimmer, depending on the light you shine on it," she said.

From Science Daily • Mar. 31, 2026

To be sure, there are questions about whether binary events contracts should be regulated—and taxed—more like gambling.

From Barron's • Mar. 21, 2026

He’s both movie-star hunky and action-star engrossing, flitting between these two deceptively binary ends without breaking a sweat.

From Salon • Mar. 21, 2026

Even in the South American binary counting schemes, linguists see the beginnings of a quinary system.

From "Zero: The Biography of a Dangerous Idea" by Charles Seife