conchoid

American  

[kong-koid] / ˈkɒŋ kɔɪd /

noun

Geometry.

1. a plane curve such that if a straight line is drawn from a certain fixed point, called the pole of the curve, to the curve, the part of the line intersected between the curve and its asymptote is always equal to a fixed distance. Equation: r = b ± a sec(θ).

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conchoid British  

/ ˈkɒŋkɔɪd /

noun

1. geometry a plane curve consisting of two branches situated about a line to which they are asymptotic, so that a line from a fixed point (the pole) intersecting both branches is of constant length between asymptote and either branch. Equation: ( x – a )²( x ² + y ²) = b ² x ² where a is the distance between the pole and a vertical asymptote and b is the length of the constant segment

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Etymology

Origin of conchoid

From the Greek word konchoeidḗs, dating back to 1790–1800. See conch, -oid

Example Sentences

The new retrospective show of paintings by Kenneth Noland�their stripes and chevrons wedged uneasily into the conchoid spaces of New York's Guggenheim Museum�provides a dismaying lesson in how critical fashions change.

From Time Magazine Archive

Then the locus of X and X′ is the conchoid.

From Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 7 "Columbus" to "Condottiere" by Various

The pileus varies from a regular wedge-shape to spathulate, or more or less irregularly petaloid, or conchoid forms, the extremes of size and form being shown in Figs.

From Studies of American Fungi. Mushrooms, Edible, Poisonous, etc. by Atkinson, George Francis

Conchoid′al, pertaining to a conchoid: shell-like, applied to the fracture of a mineral; Concholog′ical, pertaining to conchology.—ns.

From Chambers's Twentieth Century Dictionary (part 1 of 4: A-D) by Various

The conchoid has been employed by later mathematicians, notably Sir Isaac Newton, in the construction of various cubic curves.

From Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 7 "Columbus" to "Condottiere" by Various