A surface, all of whose cross sections are elliptic or circular (including the sphere), that generalises the ellipse and in Cartesian coordinates (x, y, z) is a quadric with equation x²/a² + y²/b² + z²/c² = 1.
Such a surface used as a model of the shape of the earth.
Shaped like an ellipse; elliptical.
Having the tridimensional shape of an ellipse rotated on its long axis.
Of or pertaining to an ellipse; elliptic.
Each circle, volution or equivalent in a pattern of concentric circles, ovals, arcs, or a spiral.
A circle of three or more leaves, flowers, or other organs, about the same part or joint of a stem.
A flywheel, a weight attached to a spindle.
A volution, or turn, of the spire of a univalve shell.
Any volution, as for example in the human ear or fingerprint.
To form a pattern of concentric circles.