\begin{definition}[Definition:Scope of Occurrence]
Let $\FF$ be a formal language with alphabet $\AA$.
Let $\mathbf A$ be a well-formed formula of $\FF$.
Let $a$ be a fixed occurrence of some element of $\AA$ in $\mathbf A$.
Then the '''scope''' of $a$ is the smallest well-formed part of $\mathbf A$ that contains $a$.
\end{definition}