Definition:Open Cover

Definition
Let $T = \left({S, \tau}\right)$ be a topological space.

Let $\CC$ be a cover for $S$.

Then $\CC$ is an open cover (of $T$) :
 * $\CC \subseteq \tau$

That is, all the elements of $\CC$ are open sets.

Also known as
Some sources have this as open covering.