cardioid

American  

[kahr-dee-oid] / ˈkɑr diˌɔɪd /

noun

Mathematics.

1. a somewhat heart-shaped curve, being the path of a point on a circle that rolls externally, without slipping, on another equal circle. Equation: r = a (1−cosA).

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cardioid British  

/ ˈkɑːdɪˌɔɪd /

noun

1. a heart-shaped curve generated by a fixed point on a circle as it rolls around another fixed circle of equal radius, a. Equation: r = a (1 – cos φ), where r is the radius vector and φ is the polar angle

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cardioid Scientific  

/ kär′dē-oid′ /

1. A heart-shaped plane curve, the locus of a fixed point on a circle that rolls on the circumference of another circle with the same radius.

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Etymology

Origin of cardioid

First recorded in 1745–55, cardioid is from the Greek word kardioeidḗs heart-shaped. See cardi-, -oid

Example Sentences

This cardioid condenser mic is great for podcasting and streaming, and it comes with a small desktop tripod.

From The Verge • Aug. 11, 2022

Regarding the microphone, you’ll get a HyperClear supercardioid mic with the Kaira Pro compared to a cardioid mic with the standard Kaira.

From The Verge • Nov. 16, 2021

Find the area inside the cardioid defined by the equation r = 1 − cos θ.

From Textbooks • Mar. 30, 2016

This shape is often included with the family of curves called limaçons, but here we will discuss the cardioid on its own.

From Textbooks • Feb. 13, 2015

When c = a or = ∞ the curve reduces to the cardioid or the two cusped epicycloid previously discussed.

From Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 5 "Cat" to "Celt" by Various