A circle is 2D.
A sphere is a 3D circle.
A "teardrop" 2D shape (bottom half circle, top-half kindof diamond shape) probably has a name (I don't know - someone suggested squircle which I love - because it's half square, half circle...). Maybe a lachrymaform? Maybe a symmetrical airfoil?
Anyhow - what's the name of a 3D one of these? bottom-half sphere, with the top half terminating in a sharp point?