 Besides the standard definition of a black hole based on the presence of a global event horizon, and the quasi-local definitions just discussed, there is an enormous and greatly variegated menagerie of different definitions and conceptions of a black hole that physicists in different fields (and sometimes those in the same field) use in their day to day work, none agreeing with the standard or quasi-local definitions, many of them manifestly inconsistent with each other (Curiel 2019). However one views this situation, it is clear, as a brute fact about the practice of physics today, that there is no single definition of “black hole” that will serve all investigative purposes in all fields in which black holes are objects of study.  Table 1  lists the core concepts most commonly used in definitions and characterizations of black holes across several different fields of physics, sketched with only the broadest and crudest of brushes. It should be kept in mind that many investigators in each of these fields do not use, or even accept as reasonable, what is given in the table. 