# Parabola

The parabola is the locus of points on the plane that is equidistant from a fixed point called the focus and a fixed line called the directrix.

### Elements of the Parabola

**Focus**

The focus is the fixed point **F**.

**Directrix**

The directrix is the fixed line **d**.

**Focal Parameter**

The focal parameter is the distance from the focus to the directrix. It is denoted by **p**.

**Axis**

The axis is the line perpendicular to the directrix that passes through the focus.

**Vertex**

The vertex is the point of intersection of the parabola with its axis.