An Etymological Dictionary of Astronomy and Astrophysics

1. Math.: A point at which a given mathematical object is not defined.
   

2. Physics: A point in → space-time in which gravitational force causes space-time to have infinite curvature; matter is crushed to infinite density and zero volume. This happens at the center of a → black hole where space and time cease to exist as we know them, and the known laws of physics break down. See also
   → Schwarzschild singularity; → initial singularity.

See also: → singular + → -ity.