This document defines and explains polynomial functions. A polynomial is the sum of monomials, which are terms with variables raised to whole number exponents. The degree of a polynomial is the highest exponent of the variable. The leading coefficient is the coefficient of the term with the highest degree. Polynomial functions are classified based on degree as linear, quadratic, cubic, etc. and their general shapes depend on the degree and number of possible zeros. The end behavior of a polynomial function as x approaches positive or negative infinity depends on whether the degree is even or odd and if the leading coefficient is positive or negative.