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." First applied by Apollonius of Perga (3c. B.C.E.).
1560s, "an ellipse," from Latin ellipsis, from Greek elleipsis "a falling short, defect, ellipse," from elleipein "to fall short, leave out," from en- "in" + leipein "to leave" (see relinquish). Grammatical sense first recorded 1610s.
A closed, symmetric curve shaped like an oval, which can be formed by intersecting a cone with a plane that is not parallel or perpendicular to the cone's base. The sum of the distances of any point on an ellipse from two fixed points (called the foci) remains constant no matter where the point is on the curve.
A punctuation mark (&ellipsis;) used most often within quotations to indicate that something has been left out. For example, if we leave out parts of the above definition, it can read: “A punctuation mark (&ellipsis;) used most often &ellipsis; to indicate&ellipsis4;”
In geometry, a curve traced out by a point that is required to move so that the sum of its distances from two fixed points (called foci) remains constant. If the foci are identical with each other, the ellipse is a circle; if the two foci are distinct from each other, the ellipse looks like a squashed or elongated circle.