A coefficient is a number that stands in front of a variable, an expression, or a function. Below is an algebraic expression where the terms containing variables have the coefficients $2$ and $\text{-}5.$

Coefficients indicate how many times a particular variable appears in an expression. In this case, there are two $x^3\text{-terms}$ and five $x\text{-terms}.$ $$\begin{array}{c}\underset{2}{\underbrace{\left(x^3+x^3\right)}}-\underset{5}{\underbrace{(x+x+x+x+x)}}+3\end{array}$$ Note that a variable with a coefficient of $1$ is usually written as though it doesn't have a coefficient. $$\begin{array}{c}1a=a\end{array}$$