Ratio of the distance |PF\(_{1}\)| between a point P of a conic section and a focus F\(_{1}\) and the distance |PB| from the corresponding directrix.

### Notation

The eccentricity of a conic section is denoted as “e”, which is read “eccentricity”.

Ratio of the distance |PF\(_{1}\)| between a point P of a conic section and a focus F\(_{1}\) and the distance |PB| from the corresponding directrix.

The eccentricity of a conic section is denoted as “e”, which is read “eccentricity”.