a generalized complex number consisting of four components, x = x0 + x1i + x2j + x3k, where x, x0…x3 are real numbers and i2 = j2 = k2 = –1, ij = –ji = k, etc
2. another word for quaternary (sense 5)
Word origin
C14: from Late Latin quaterniōn, from Latin quaternī four at a time
quaternion in American English
(kwəˈtɜrniən; kwɑˈtɜrniən)
noun
1.
a set of four
2. Ancient Mathematics
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