Singularity

A gravitational singularity is a point in space where the force of gravity (as measured by the curvature of spacetime or the density of matter) becomes infinite. The typical example of a singularity is the point in space at the center of a black hole.

Singularities in Science Fiction

Singularities are occasionally used as weapons or power sources in science fiction. Star Trek tends to refer to them as "quantum singularities".

Romulan starships

Romulan starships, including the D'deridex-class Warbird, use an artificial quantum singularity to power the ship. This means that Romulan starships don't experience the hazards of carrying antimatter fuel for a warp core, but the quantum singularity would have safety issues of its own, since an uncontrolled singularity would consume a starship. Apparently some alien life forms use singularities as breeding grounds, and this can interfere with the operation of the Romulan power system.