The word “quadratic” is derived from the word “quad” which means square because the variable gets squared. In other words, a quadratic function is a polynomial function of degree 2. A quadratic function has a minimum of one term which is of the second degree. It is an algebraic function.

The single defining feature of quadratic function is that they are of the second degree or of degree two. This means that in all quadratic function, the highest exponent of x in a nonzero term is equal to two. For example, f(x) = 2x², g(x) = x² +3x -8, y = 7-x² + 3x and y = 3x² -5x + 7 are quadratic functions.