Resolvable space

Origin
The term resolvable space was introduced by E. Hewitt in 1943.

Definition
A topological space is said to be resolvable if it has two disjoint dense subsets. Note that since any subset containing a dense subset is dense, this is equivalent to saying that it is expressible as a union of two disjoint dense subsets.

Note that by this definition, the one-point space is not a resolvable space, but the empty space is a resolvable space.

Examples
The real numbers form a resolvable space. The rationals and irrationals both form disjoint dense subsets.