ellipse (n.) Look up ellipse at Dictionary.com
1753, from French ellipse (17c.), from Latin ellipsis "ellipse," also, "a falling short, deficit," from Greek elleipsis (see ellipsis). So called because the conic section of the cutting plane makes a smaller angle with the base than does the side of the cone, hence, a "falling short." The Greek word was first applied by Apollonius of Perga (3c. B.C.E.). to the curve which had been previously called the section of the acute-angled cone, but it had previously been technically applied to a rectangle one of whose sides coincides with a part of a given line (Euclid, VI. 27).