[ kahr-dee-oid ]
/ ˈkɑr diˌɔɪd /

noun Mathematics.

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).

Nearby words

  1. cardiogram,
  2. cardiograph,
  3. cardiographic,
  4. cardiography,
  5. cardiohepatic,
  6. cardioinhibitory,
  7. cardiokinetic,
  8. cardiokymogram,
  9. cardiokymograph,
  10. cardiolipin

Origin of cardioid

First recorded in 1745–55, cardioid is from the Greek word kardioeidḗs heart-shaped. See cardi-, -oid Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for cardioid


/ (ˈkɑːdɪˌɔɪd) /


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
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Science definitions for cardioid


[ kärdē-oid′ ]

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.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.