Ellipses

[ih-lips] /ɪˈlɪps/

noun, Geometry.
1.
a plane curve such that the sums of the distances of each point in its periphery from two fixed points, the foci, are equal. It is a conic section formed by the intersection of a right circular cone by a plane that cuts the axis and the surface of the cone. Typical equation: (x 2 / a 2) + (y 2 / b 2) = 1. If a = b the ellipse is a circle.
[ih-lip-sis] /ɪˈlɪp sɪs/
noun, plural ellipses
[ih-lip-seez] /ɪˈlɪp siz/ (Show IPA)
1.
Grammar.

2.
Printing. a mark or marks as ——, …, or * * *, to indicate an omission or suppression of letters or words.
/ɪˈlɪps/
noun
1.
a closed conic section shaped like a flattened circle and formed by an inclined plane that does not cut the base of the cone. Standard equation x²/a² + y²/b² = 1, where 2a and 2b are the lengths of the major and minor axes. Area: πab
/ɪˈlɪpsɪs/
noun (pl) -ses (-siːz)
1.
Also called eclipsis. omission of parts of a word or sentence
2.
(printing) a sequence of three dots (…) indicating an omission in text
n.

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.).
n.

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.
ellipse
(ĭ-lĭps’)
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.
ellipsis [(i-lip-sis)]

A punctuation mark (…) 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 (…) used most often … to indicate….”
ellipse [(i-lips)]

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.

Note: The orbits of the planets and of many comets are ellipses.