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n. [ Gr. 'e`lleipsis, prop., a defect, the inclination of the ellipse to the base of the cone being in defect when compared with that of the side to the base: cf. F. ellipse. See Ellipsis. ] 1. (Geom.) An oval or oblong figure, bounded by a regular curve, which corresponds to an oblique projection of a circle, or an oblique section of a cone through its opposite sides. The greatest diameter of the ellipse is the major axis, and the least diameter is the minor axis. See Conic section, under Conic, and cf. Focus. [ 1913 Webster ]

2. (Gram.) Omission. See Ellipsis. [ 1913 Webster ]

3. The elliptical orbit of a planet. [ 1913 Webster ]

The Sun flies forward to his brother Sun;
The dark Earth follows wheeled in her ellipse. Tennyson. [ 1913 Webster ]

n.; pl. Ellipses [ L., fr. Gr. 'e`lleipsis a leaving, defect, fr. 'ellei`pein to leave in, fall short; 'en in + lei`pein to leave. See In, and Loan, and cf. Ellipse. ] 1. (Gram.) Omission; a figure of syntax, by which one or more words, which are obviously understood, are omitted; as, the virtues I admire, for, the virtues which I admire. [ 1913 Webster ]

2. (Geom.) An ellipse. [ Obs. ] [ 1913 Webster ]

3. (Printing) a printing symbol, usually three periods in a row (. . .), indicating the omission of some part of a text; -- used commonly in quotations, so as to suppress words not essential to the meaning. A long dash (---) and three asterisks (* * *) are sometimes used with the same meaning. [ PJC ]

n. [ Ellipse + graph: cf. F. ellipsographe. ] An instrument for describing ellipses; -- called also trammel. [ 1913 Webster ]

n. [ Ellipse + -oid: cf. F. ellipsoide. ] (Geom.) A solid, all plane sections of which are ellipses or circles. See Conoid, n., 2 (a). [ 1913 Webster ]

☞ The ellipsoid has three principal plane sections, a, b, and c, each at right angles to the other two, and each dividing the solid into two equal and symmetrical parts. The lines of meeting of these principal sections are the axes, or principal diameters of the ellipsoid. The point where the three planes meet is the center. [ 1913 Webster ]

Ellipsoid of revolution, a spheroid; a solid figure generated by the revolution of an ellipse about one of its axes. It is called a prolate spheroid, or prolatum, when the ellipse is revolved about the major axis, and an oblate spheroid, or oblatum, when it is revolved about the minor axis.

{ } a. Pertaining to, or shaped like, an ellipsoid; as, ellipsoid or ellipsoidal form.

{ } a. [ Gr. &unr_;: cf. F. elliptique. See Ellipsis. ] 1. Of or pertaining to an ellipse; having the form of an ellipse; oblong, with rounded ends. [ 1913 Webster ]

The planets move in elliptic orbits. Cheyne. [ 1913 Webster ]

The billiard sharp who any one catches,
His doom's extremely hard --
He's made to dwell
In a dungeon cell
On a spot that's always barred.
And there he plays extravagant matches
In fitless finger-stalls
On a cloth untrue
With a twisted cue
And elliptical billiard balls!
Gilbert and Sullivan (The Mikado: The More Humane Mikado Song)

2. Having a part omitted; as, an elliptical phrase. [ 1913 Webster ]

3. leaving out information essential to comprehension; so concise as to be difficult to understand; obscure or ambiguous; -- of speech or writing; as, an elliptical comment. [ PJC ]

Elliptic chuck. See under Chuck. --
Elliptic compasses, an instrument arranged for drawing ellipses. --
Elliptic function. (Math.) See Function. --
Elliptic integral. (Math.) See Integral. --
Elliptic polarization. See under Polarization. [ 1913 Webster ]

adv. 1. In the form of an ellipse. [ 1913 Webster ]

2. With a part omitted; as, elliptically expressed. [ 1913 Webster ]

n. [ Cf. F. ellipticité. ] Deviation of an ellipse or a spheroid from the form of a circle or a sphere; especially, in reference to the figure of the earth, the difference between the equatorial and polar semidiameters, divided by the equatorial; thus, the ellipticity of the earth is 1/29966. [ 1913 Webster ]

☞ Some writers use ellipticity as the ratio of the difference of the two semiaxes to the minor axis, instead of the major. Nichol. [ 1913 Webster ]