OV or TOV?

•Equilibrium in static spherical stars has been studied in the literature.•The relevant equation is referred to with two names, OV or TOV (more popular).•We compare Tolman׳s and Oppenheimer & Volkoff׳s papers.•We find that they adopt diametrically opposite approaches to the same problem.•The equation is a product of the OV approach, so should be called the OV equation.

The well-known equation for hydrostatic equilibrium in a static spherically symmetric spacetime supported by an isotropic perfect fluid is referred to as the Oppenheimer-Volkoff (OV) equation or the Tolman-Oppenheimer-Volkoff (TOV) equation in various General Relativity textbooks or research papers. We scrutinize the relevant original publications to argue that the former is the more appropriate terminology.