The degree of a polynomial is the highest degree of its monomials. For example, the following polynomial has the degree $5.$ $$\begin{array}{c}4x^5+x^3-9x-84\end{array}$$ This is because the monomial with highest degree is $4x^5.$ If the polynomial consists of only constant terms, the polynomial has the degree $0.$ Depending on the degree of a polynomial, it can have different characteristics. For example, a polynomial with degree $1$ is linear, and a polynomial with degree $2$ is quadratic.