adjective

boolean

BOO-lee-uhn

Boolean (adjective) means relating to a system of logic in which every statement is either true or false, with nothing in between, and statements are combined using operations such as and, or and not. Example: “The filter uses boolean logic, so a record has to satisfy both conditions to appear.”

adjective

Relating to a system of logic in which every statement is either true or false, with nothing in between, and statements are combined using operations such as and, or and not.

"The filter uses boolean logic, so a record has to satisfy both conditions to appear."

"Boolean search lets you exclude a word by putting not in front of it."

noun

computing A value in a program that can only be one of two things, true or false, often used to record whether something is switched on, finished or allowed.

"Store it as a boolean rather than the text yes or no."

"The function returns a boolean: true if the email address is valid, false if it is not."

How to Use Boolean

Learner’s notes

In plain EnglishSomething that can only be true or false, with no middle option.

When to use it

Standard in mathematics, computing and library search; rare in everyday speech.

Memory tip

Programmers commonly shorten it to bool, said like the word bowl with an oo sound: bool.

Trace the full origin ↓

Easily confused with

binary → bitwise integer → conditional →

Common pairings

boolean value boolean logic boolean operator boolean search return a boolean

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Fill the Gap

Can you complete this real example?

The filter uses _____ logic, so a record has to satisfy both conditions to appear.

Etymology

From the surname of George Boole, the nineteenth-century English mathematician whose work on the algebra of logic the term commemorates, plus the adjectival ending -an.

Origin: English

Synonyms

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logical binary two-valued bool flag truth value true/false value

Related Words

number reasonable flag consistent intellectual dual logical colours

Rhymes for boolean

lean bean wean dean jean Sean mean Kean clean glean ocean Korean

See all rhymes for boolean →

Frequently Asked Questions

Why is boolean capitalised sometimes?

Because it comes from a person's name, George Boole, it is often written Boolean with a capital B, especially in mathematics and formal writing. In programming, where bool and boolean are keywords, the lower-case form is usual.

What is a boolean in programming?

It is a value that can only be true or false. Programs use it for yes-or-no facts, such as whether a user is logged in, and for deciding which branch of code to run next.

What are the boolean operators?

The three basic ones are and, or and not. And is true only when both sides are true, or is true when at least one side is true, and not reverses a value from true to false or the other way round.

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