n.
Pronunciation: ' kär-d ē - ˌ o ̇ id
Function: noun
Date: 1753
: a heart-shaped curve that is traced by a point on the circumference of a circle rolling completely around an equal fixed circle and has an equation in one of the forms ρ = a (1 ± cos θ ) or ρ = a (1 ± sin θ ) in polar coordinates
cardioid