A monomial is an algebraic expression with only one term. Monomial expressions involve the multiplication or division of numbers and variables in some valid combination. $\begin{array}{c|c} z^5 & {\color{#009600}{\Large{\checkmark}}} \\ \hline\\[-1em] 2x & {\color{#009600}{\Large{\checkmark}}} \\ \hline\\[-1em] \dfrac{\text{-} 7yz^4}{2} & {\color{#009600}{\Large{\checkmark}}} \end{array}$ Note, the exponents of the variables in a monomial are whole numbers and a monomial cannot have variables in its denominator. $\begin{array}{c|c} m^{\frac{4}{7}} & {\color{#FF0000}{\Large{\mathbf{\times}}}} \\ \hline\\[-1em] g^{\text{-} 3} & {\color{#FF0000}{\Large{\mathbf{\times}}}} \\ \hline\\[-1em] \dfrac{1}{x} & {\color{#FF0000}{\Large{\mathbf{\times}}}} \end{array}$ When multiple monomials are put together, separated by $+$ or $-$ signs, they are the terms that form polynomials.