These example sentences are selected automatically from various online news sources to reflect current usage of the word 'ellipse.' We understand! It has two focal points. An ellipse is a figure bounded by a continuous curve, whose nature will be shown presently. Keep the string stretched so it forms a triangle, and draw a curve ... you will draw an ellipse.It works because the string naturally forces the same distance from pin-to-pencil-to-other-pin. Ellipse is 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. Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Therefore, from this definition the equation of the ellipse is: r 1 + r 2 = 2a, where a = semi-major axis. In most definitions of the conic sections, the circle is defined as a special case of the ellipse, when the plane is parallel to the base of the cone. If one thing travels around another in the shape of an ellipse â like the earth around the sun â it has an elliptical orbit. An oval may or may not fit the definition of an ellipse. Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free! F1 and F2 are two fixed points called foci. Send us feedback. The elongation of an ellipse is measured by its eccentricity $${\displaystyle e}$$, a number ranging from $${\displaystyle e=0}$$ (the limiting case of a circle) to $${\displaystyle e=1}$$ (the limiting case of infinite elongation, no longer an ellipse but a parabola). In mathematics, an ellipse is a plane curve surrounding two focal points, such that for all points on the curve, the sum of the two distances to the focal points is a constant. Ellipse The moon's orbit around Earth is in the shape of an ellipse. The American Heritage® Science Dictionary A solar eclipse occurs when the moon passes between the sun and the earth; a lunar eclipse when the earth passes between the sun and ⦠An ellipse is formed when a cone is intersected by a plane at an angle with respect to its base. Definition of ellipse in the Definitions.net dictionary. Given the graph of an ellipse, find its equation, and vice versa. Put two pins in a board, put a loop of string around them, and insert a pencil into the loop. Learn a new word every day. Which Word of the Day means “happening within or being the created world of a story”? An ellipse is defined as the locus of all points in the plane for which the sum of the distances r1 and r2 to two fixed points F1 and F2 (called the foci) separated by a distance 2c, is a given constant 2a. It may be defined as the path of a point moving in a plane so that the ratio of its distances from a fixed point (the focus) and a fixed straight line (the directrix) is a constant less than one. Published by Houghton Mifflin Harcourt Publishing Company. Science ellipses. 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. 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. The definition of elliptical is something that resembles or relates to an ellipse, a plane that intersects a cone. One property of an ellipse is that the reflection off its boundary of a line from one focus will pass through the other. In geometry, an ellipse is a two-dimensional shape, that is defined along its axes. The ellipse is symmetrical along two lines, called axes. In mathematics, an ellipse is a plane algebraic curve where the sum of the distances from any point on the curve to two fixed points is constant. Take this quiz on the Words of the Day from February, 2021, to show that you’re far from frumious! circa 1753, in the meaning defined at sense 1a, It's time to stop calling them 'dot dot dot'. In the illustration, denote the distance between two points, F, F â² of a plane by 2 c, c > 0, and let 2 a be a constant, with a > c. [>>>] An ellipse is one of the shapes called conic sections, which is formed by the intersection of a plane with a right circular cone. The same ellipse is also represented by the parametric equations: