An egg-shaped curve. Lockwood (1967) calls the negative pedal curve of an ellipse with eccentricity an ovoid.
Ovoid
See also
Burleigh's Oval, OvalExplore with Wolfram|Alpha
References
Lockwood, E. H. A Book of Curves. Cambridge, England: Cambridge University Press, p. 157, 1967.Referenced on Wolfram|Alpha
OvoidCite this as:
Weisstein, Eric W. "Ovoid." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Ovoid.html