2. (Math.) The ratio of the distance between the center and
the focus of an ellipse or hyperbola to its
semi-transverse axis.
3. (Astron.) The ratio of the distance of the center of the
orbit of a heavenly body from the center of the body round
which it revolves to the semi-transverse axis of the
orbit.
4. (Mech.) The distance of the center of figure of a body, as
of an eccentric, from an axis about which it turns; the
throw.