The document defines different types of algebraic expressions including monomials, binomials, and trinomials which are polynomials containing 1, 2, or 3 terms respectively. It provides examples of polynomials and discusses how to classify polynomials based on the number of terms and order the terms from highest to lowest degree with the leading coefficient being the coefficient of the highest degree term. The document also notes things that are not considered polynomials such as expressions with variables in radicals, negative exponents, or denominators.