/eks"ak'sis/ , n. , pl. x-axes /eks"ak'seez/ . Math.
1. Also called axis of abscissas . (in a plane Cartesian coordinate system) the axis, usually horizontal, along which the abscissa is measured and from which the ordinate is measured. See diag. under abscissa .
2. (in a three-dimensional Cartesian coordinate system) the axis along which values of x are measured and at which both y and z equal zero.
[ 1925-30 ]