Definition:Well-Formed Formula

Definition
Let $\mathcal F$ be a formal language whose alphabet is $\mathcal A$.

A well-formed formula is a collation in $\mathcal A$ which can be built by using the rules of formation of the formal grammar of $\mathcal F$.

That is, a collation in $A$ is a well-formed formula in $\mathcal F$ iff it has a parsing sequence in $\mathcal F$.

Also known as
This is often encountered in its abbreviated form WFF, pronounced something like woof or oof, depending on personal preference.

Alternative names include well-formed word or simply formula.