Definition:Labeled Tree for Propositional Logic/Child WFF

Definition
Let $\left({T, \mathbf H, \Phi}\right)$ be a labeled tree for propositional logic. A WFF that is attached to a child of a node $t$ is called a child WFF of $t$.

Also known as
A child WFF of $t$ is also referred as just a child of $t$.

When using the term child in this way, take care to avoid confusion with the concept of child node.