# quaternion

> English word · Noun · IPA /kwəˈtɜːni.ən/

## Definitions
1. A group or set of four people or things.
2. A word of four syllables.
3. A type of four-dimensional hypercomplex number consisting of a real part and three imaginary parts (real multiples of distinct, independent square roots of −1 denoted by i, j and k); commonly used in vector mathematics and as an alternative to matrix algebra in calculating the rotation of three-dimensional objects.

## Etymology
From Middle English quaterniǒun, from Late Latin quaterniō, from quaternī (“four each”) + -iō, from quater (“four times”). Doublet of kern. The mathematics sense was coined by Irish mathematician and astronomer William Rowan Hamilton in 1843.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/quaternion