Eccentricity
A quantity defined for a Conic Section which can be given in terms of Semimajor andSemiminor Axes for an Ellipse. For an Ellipse with Semimajor Axis 
andSemiminor Axis 
,
The eccentricity can be interpreted as the fraction of the distance to the semimajor axis at which the Focus lies,
where
is the distance from the center of the Conic Section to the Focus.The table below gives the type of Conic Section corresponding to various ranges of eccentricity 
. | Curve |
 | Circle |
 | Ellipse |
 | Parabola |
 | Hyperbola |
- Shoe Surface
- Shortening
- Shuffle
- Siamese Dodecahedron
- Siamese Method
- Sibling
- Sicherman Dice
- Sici Spiral
- Side
- Sidon Sequence
- Siegel Disk Fractal
- Siegel Modular Function
- Siegel's Paradox
- Siegel's Theorem
- Sierpinski Arrowhead Curve
- Sierpinski Carpet
- Sierpinski Constant
- Sierpinski Curve
- Sierpinski Gasket
- Sierpinski-Menger Sponge
- Sierpinski Number of the First Kind
- Sierpinski Number of the Second Kind
- Sierpinski's Composite Number Theorem
- Sierpinski Sieve
- Sierpinski Sponge