\begin{definition}[Definition:Constant Term of Polynomial]
Let $R$ be a commutative ring with unity.
Let $P \in R \sqbrk X$ be a nonzero polynomial over $R$:
:$\ds f = \sum_{k \mathop = 0}^n a_k \circ x^k$
where $n$ is the degree of $P$.
The '''constant term''' of $P$ is the coefficient of $a_0$.
\end{definition}