Vertex:The point on the graph of a quadratic function that represents the maximum or minimum value of the function, where the function changes direction.
Parabola:The U-shaped curve that is the graph of a quadratic function, which opens upward or downward depending on the sign of the leading coefficient.
Concavity:The curvature of a function, which determines whether the function is increasing or decreasing at a given point. Quadratic functions have concavity that is either upward or downward.