- a set of four
- Math. an expression that is the sum of four terms, one of which is real and three of which contain imaginary units, and that can be written as the sum of a scalar and a three-dimensional vector
Origin of quaternionMiddle English from Late Latin quaternio from Classical Latin quaterni: see quaternary
- A set of four persons or items.
- Mathematics Any number of the form a + bi + cj + dk where a, b, c, and d are real numbers, ij = k, i 2 = j 2 = −1, and ij = − ji. Under addition and multiplication, quaternions have all the properties of a field, except multiplication is not commutative.
Origin of quaternionMiddle English quaternioun from Late Latin quaterniō quaterniōn- from Latin quaternī by fours from quater four times ; see kwetwer- in Indo-European roots.
- A group or set of four people or things.
- A word of four syllables.
- (mathematics) A four-dimensional hypercomplex number that consists of a real dimension and 3 imaginary ones (i, j, k) that are each a square root of -1. They are commonly used in vector mathematics and in calculating the rotation of three-dimensional objects.
From Middle English quaternioun, from Late Latin quaterniÅ, from quaternÄ« (ablative form of quater, “four times") + -iÅn, “-ion".