event horizon Word Origin noun Astronomy.
- the boundary around a black hole on and within which no matter or radiation can escape.
Origin of event horizon First recorded in 1970–75 British Dictionary definitions for event horizon event horizon noun
- astronomy the surface around a black hole enclosing the space from which electromagnetic radiation cannot escape due to gravitational attraction. For a non-rotating black hole, the radius is proportional to the mass of the black hole
event horizon in Science event horizon [ĭ-vĕnt′]
- A spatial boundary around a black hole inside which gravity is strong enough to prevent all matter and radiation from escaping. The inability of even light to escape this region is what gives black holes their name.