A parabola is a symmetrical, U-shaped curve that can open either upward or downward. It is defined as the set of all points that are equidistant from a fixed point called the focus and a fixed line known as the directrix. Parabolas are commonly found in mathematics and physics, particularly in the study of quadratic functions. In the coordinate plane, the standard equation of a parabola is written as y = ax^2 + bx + c, where a, b, and c are constants. The value of a determines the direction and width of the parabola. Parabolas also appear in real-life applications, such as the shape of satellite dishes and the trajectory of projectiles.