lemniscate

American  

[lem-nis-kit, lem-nis-keyt, -kit] / lɛmˈnɪs kɪt, ˈlɛm nɪsˌkeɪt, -kɪt /

noun

Analytic Geometry.

1. a plane curve generated by the locus of the point at which a variable tangent to a rectangular hyperbola intersects a perpendicular from the center to the tangent. Equation: r 2 = 2 a 2 cosθ.

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lemniscate British  

/ ˈlɛmnɪskɪt /

noun

1. a closed plane curve consisting of two symmetrical loops meeting at a node. Equation: ( x ² + y ²)² = a ²( x ² – y ²), where a is the greatest distance from the curve to the origin. The symbol for infinity (∞) is an example

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Etymology

Origin of lemniscate

First recorded in 1775–85, lemniscate is from the Latin word lēmniscātus adorned with ribbons. See lemniscus, -ate ¹

Explanation

If a mathematician uses the word lemniscate, they're just using fancy math jargon to mean "shape of a sideways figure eight." When you write out the number eight and turn it on its side like an infinity symbol, it's a lemniscate. Mathematicians use the word for algebraic curves that take that exact shape, two symmetrical loops meeting at a center point. If you imagine a length of string in the form of a sideways 8, it makes sense that lemniscate comes from the Late Latin lemniscus, "a ribbon" and its Greek root lēmniskos, "a woolen ribbon."

Example Sentences

Centered at the pole, a lemniscate is symmetrical by definition.

From Textbooks • Feb. 13, 2015

Blavatsky, as to how the chemical elements were deposited by a spiral evolutive force, a creative impulse working outward in the form of a caduceus or lemniscate, or figure '8.'

From The Crest-Wave of Evolution A Course of Lectures in History, Given to the Graduates' Class in the Raja-Yoga College, Point Loma, in the College-Year 1918-19 by Morris, Kenneth

Some projective-geometrical considerations concerning the lemniscate are to be found in the previously mentioned writings of G. Adams and L. Locher-Ernst.

From Man or Matter by Lehrs, Ernst