Parabola is the locus of a point P which moves in a plane so that its distance from a fixed line of the plane and its distance from a fixed point of the plane, not on the line, are equal.
The fixed point F is called the focus and fixed line is called the directrix of the parabola.
The perpendicular to the directrix from the focus is called the axis of the parabola.
The intersection of the parabola and the axis of the parabola is called vertex.
Vertex is the mid point of axis.
The line joining any two distinct points of the parabola is called a chord.
A chord which passes through the focus is called a focal chord.
The distance between the focus and any point of the focal chord is called focal radius.
The focal chord which is perpendicular to the axis is called the latus rectum