Math. a curve more or less in the shape of a heart, traced by a point on the circumference of a circle that rolls around the circumference of another equal circle
Origin of cardioidClassical Greek kardioeid?s, heart-shaped ; from kardia, heart + -oeid?s, -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 parametric equations of this cardioid are
x = -a cos &thgr; (1 - cos &thgr;),
y = a sin &thgr; (1 - cos &thgr;).
(comparative more cardioid, superlative most cardioid)
- Having this characteristic shape
cardio- + -oid