[L. ordinatus.] Regular; methodical. An ordinate figure is one whose sides and angles are equal.

In geometry and conic sections, a line drawn from any point of the circumference of an ellipsis or other conic section, perpendicularly across the axis to the other side.

An ordinate is a line drawn perpendicular to the axis of a curve and terminating the curvilinear space.

Ordinates of a curve, right lines parallel to one another, terminated by the curve, and bisected by a right line called the diameter.