In mathematics, the algebraic expression formed by adding several monomials is called polynomial (if there is subtraction, subtracting a number is equal to adding its inverse). Each monomial in a polynomial is called a polynomial term, and the highest degree of these monomials is the degree of this polynomial.
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.