## cardioid

[kär**′**dē o̵id′]

noun

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 cardioid

Classical Greek*kardioeidēs*, heart-shaped ; from

*kardia*, heart +

*-oeidēs*, -oid

## cardioid

noun

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.

**cardioid**

The parametric equations of this cardioid are

x = -a cos &thgr; (1 - cos &thgr;),

y = a sin &thgr; (1 - cos &thgr;).

## cardioid

Noun

(*plural* cardioids)

- (geometry) An epicycloid with exactly one cusp; the plane curve with polar equation - having a shape supposedly heart-shaped

Adjective

(*comparative* more cardioid, *superlative* most cardioid)

- Having this characteristic shape

Origin

*cardio-* + *-oid*