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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.

A portion of a curved line; as, the arc of a circle or of an ellipse.

the curve into two symmetrical portions, as in the parabola, which has one such axis, the ellipse, which has two, or the circle, which has an infinite number. The two axes of the ellipse are the major axis and the minor axis, and the two axes of the hyperbola are the transverse axis and the conjugate axis. -- Axis of…

epler discovered that the various observed positions of the planet Mars were points in an ellipse. "The colligation of facts." Whewell. Colligation is not always induction, but induction is always colligation. J. S. Mill.

rsection of the surface of a right cone and a plane. The conic sections are the parabola, ellipse, and hyperbola. The right lines and the circle which result from certain positions of the plane are sometimes, though not generally included. -- Conic sections, that branch of geometry which treats of the parabola, ellips…

line through the two foci. -- Conjugate diameters (Conic Sections), two diameters of an ellipse or hyperbola such that each bisects all chords drawn parallel to the other. -- Conjugate focus (Opt.) See under Focus. -- Conjugate mirrors (Optics), two mirrors so placed that rays from the focus of one are received at…

one in which the major proposition is disjunctive; as, the earth moves in a circle or an ellipse; but in does not move in a circle, therefore it moves in an ellipse.

Not having the same center; -- said of circles, ellipses, spheres, etc., which, though coinciding, either in whole or in part, as to area or volume, have not the same center; -- opposed to concentric.

The ratio of the distance between the center and the focus of an ellipse or hyperbola to its semi-transverse axis.

An ellipse. [Obs.]

An instrument for describing ellipses; -- called also trammel.

A solid, all plane sections of which are ellipses or circles. See Conoid, n., 2 (a).

Of or pertaining to an ellipse; having the form of an ellipse; oblong, with rounded ends. The planets move in elliptic orbits. Cheyne.

In the form of an ellipse.

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

lace of a planet as supposed to move uniformly in a circle, and its place as moving in an ellipse. -- Equations of condition (Math.), equations formed for deducing the true values of certain quantities from others on which they depend, when different sets of the latter, as given by observation, would yield different v…

of functions, so called because one of the forms expresses the relation of the arc of an ellipse to the straight lines connected therewith. -- Explicit function, a quantity directly expressed in terms of the independently varying quantity; thus, in the equations y = 6x2, y = 10 -x3, the quantity y is an explicit func…

on of the surface with a parallel to the tangent plane and indefinitely near it. It is an ellipse when the curvature is synclastic, and an hyperbola when the curvature is anticlastic.

thematics; -- so called because one of the integrals expresses the length of an arc of an ellipse.

d by John Kepler. They are these: (1) The orbit of a planet with respect to the sun is an ellipse, the sun being in one of the foci. (2) The areas swept over by a vector drawn from the sun to a planet are proportioned to the times of describing them. (3) The squares of the times of revolution of two planets are in the…