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