A typical black hole is always specified by

A black hole is fundamentally defined as a region of spacetime from which nothing, including light, can escape [1]. This boundary is known as the event horizon. According to the Schwarzschild metric, the event horizon is a critical surface where the gravitational pull becomes so intense that escape is impossible [2]. While general relativity predicts a curvature singularity at the center where density becomes infinite and physical laws break down [2], the defining feature that specifies an object as a black hole to the outside universe is its horizon. The 'no-hair theorem' further specifies that a black hole is characterized by only three observable parameters: mass, charge, and angular momentum [1]. However, the presence of an event horizon is the universal requirement for the classification of a black hole, separating the internal singularity from the rest of the universe.

Sources

1. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 1: The Universe, The Big Bang Theory, Galaxies & Stellar Evolution > Black holes > p. 15
2. [2] https://www.damtp.cam.ac.uk/user/tong/gr/grhtml/S6.html