transcription, транскрипция: [ ˈkär-dē-ˌȯid ]
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: ABP fixed circle; PCD first position of rolling circle; P tracing point; PM diameter through P; P 1 , P 2 , P 3 , P 4 various positions of P; P 1 M 1 , P 2 M 2 , P 3 M 3 , P 4 M 4 various positions of PM
]