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A stellar-mass black hole (aka stellar black hole or stellar remnant black hole) is a black hole that is a stellar remnant, the remains of a star. They fall within the mass-range of stars, on the order of 5-50 solar masses. They result from stars of considerable mass (less massive stars either just cool, become white dwarfs or neutron stars), but are thought to lose considerable mass before becoming black holes, from strong stellar wind as post-main-sequence stars and the possible core collapse supernova. The mass range is bounded by mass gaps (black hole mass gap or BH mass gap), i.e., mass ranges in which no black holes are found or should be found. The lower mass gap (less than 5 solar masses) is observed but with as yet no consensus explanation. The upper mass gap stems from theory, but a few apparent exceptions have been observed and need explanation.
Identification of stellar-mass black holes is often less than certain, so discoveries are often classified as black hole candidates for considerable time, and some astronomers might consider all current detections to be in that category. Some tens of candidates are known within the Milky Way. Detection is either from interaction with a binary companion (e.g., an X-ray binary, with X-rays from accretion, a microquasar), or if no such interaction provides a clue (i.e., a dormant stellar-mass black hole), orbits or other kinematics may indicate an unobserved massive object that should be observed if it is not a black hole.
Some extragalactic stellar-mass black holes' presence are revealed by GW detections.