Answer:
A parabola is the set of all points in the plane equidistant from a given line and a given point not on the line.
A parabola is the set of all points in the plane equidistant from directrix and focus.
Explanation:
A parabola is the set of all points in the plane equidistant from a given line and a given point not on the line.
The line is called directrix and the point is called focus.
So a parabola is the set of all points in the plane equidistant from directrix and focus.