Meaning of QUATERNION in English
/kweuh terr"nee euhn/ , n.
1. a group or set of four persons or things.
2. Bookbinding. four gathered sheets folded in two for binding together.
a. an expression of the form a + bi + cj + dk, where a, b, c, and d are real numbers; i 2 = j 2 = k 2 = -1; and ij = -ji = k, jk = -kj = i, and ki = -ik = j.
b. a quantity or operator expressed as the sum of a real number and three complex numbers, equivalent to the quotient of two vectors. The field of quaternions is not commutative under multiplication.
[ 1350-1400; ME quaternioun quaternion- (s. of quaternio ), equiv. to L quatern ( i ) four at a time + -ion- -ION ]
Random House Webster's Unabridged English dictionary. Полный английский словарь Вебстер - Random House . 2012