# Definition:Subset/Superset

## Definition

If $S$ is a subset of $T$, then $T$ is a superset of $S$.

This can be expressed by the notation $T \supseteq S$.

This can be interpreted as $T$ includes $S$, or (more rarely) $T$ contains $S$.

Thus $S \subseteq T$ and $T \supseteq S$ mean the same thing.

## Also known as

The term superset is rare in the literature.

Instead of $T$ is a superset of $S$, the usual terminology is $T$ contains $S$ or $T$ includes $S$.