What does "bool" mean?

A Boolean variable (one whose value is either true or false).

What is a synonym for "bool"?

Common synonyms include: boolean, cool.

noun, verb, slang

noun, verb, slang ·Moderate ·College level

Noun

1
A Boolean variable (one whose value is either true or false).
"The base class BitArray acts just like a normal C++ array of bools, although you are of course free to interpret the bits as integers […]"

Verb

1
To relax or hang out (especially with someone). slang
"I'm going to go bool with the boys."

"The base class BitArray acts just like a normal C++ array of bools, although you are of course free to interpret the bits as integers […]"

Etymology 1

From a keyword in C++ and derived programming languages, short for Boolean.

Etymology 2

Likely from replacement of the 'c' in cool.

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.