A polynomial is several terms, so it is called several terms. In polynomial, each monomial is called a term of polynomial; The highest degree of each term is called the degree of the polynomial. A polynomial is several terms, so it is called several terms. For example, x 4+x 2-44 is a quartic trinomial, that is, the highest degree of this polynomial is quartic and consists of three monomials. Mathematically, polynomial refers to the expressions of variables, coefficients and their addition, subtraction and multiplication (non-negative integer power). More broadly, the sum of 1 or 0 monomials is also a polynomial. According to this definition, polynomials are algebraic expressions. In fact, there is no theorem that is valid only for narrow polynomials but not for monomials. When 0 is a polynomial, the degree is defined as negative infinity (or 0). Monomial and polynomial are collectively called algebraic expressions. Items without letters in polynomials are called constant terms. For example, 6 in 5X+6 is a constant term.