Singularity (noun)

1. The state or quality of being singular or unique.
2. A point or region in space-time at which gravitational forces cause matter to have an infinite density and infinitesimal volume, and space and time to become infinitely distorted.

Origin:

Late middle english (in the sense "uniqueness, rarity"): from old french singularite or latin singularitas, from singularis "unique".

Examples:

1. The uniqueness of the event was its singularity.
2. The black hole is surrounded by an event horizon, beyond which the gravitational pull is so strong that nothing can escape, including light; this region is called the black hole singularity.
3. The singularity in the center of a black hole is where the laws of physics break down.
4. The singularity of the project was its unexpected success.
5. The singularity of the invention was its small size and high efficiency.