Meaning of cardioid

car•di•oid

Pronunciation: (kär'dē-oid"), [key]
— n. Math.
  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:(1−cosA). r = a
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.
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