Type variable

A placeholder (e.g., $T$, $U$, $\begin{array}{l}\\ alpha\end{array}$) representing an unknown or generic type - gets instantiated to a concrete type during type checking or remains polymorphic.

A placeholder (e.g., $T$, $U$, $\alpha$) representing an unknown or generic type - gets instantiated to a concrete type during type checking or remains polymorphic.