Black hole: when a celestial body collapses under its own weight, so the mass it is compressed in an infinitely small and dense point of a region of space, called "singularity". Recent mathematical demonstrations, performed by means of Einstein's general theory of relativity, they indicate that a black hole is one of the simplest natural objects and can be completely described by only three quantities: its mass, its angular momentum and its total electric charge.
Singularity: region of space that undergoes an infinitely large curvature, making the celestial body infinitely small and dense where all its collapsed mass is concentrated. There is no escape from the singularity: every object and even the light when it gets too close to black hole is sucked and crushed.
Glossary
Superconductors may shed light on the black hole information paradox
NASA | Massive Black Hole Shreds Passing Star
MAQ/April 2018/24