standard electrode potential, \(E^{\unicode{x26ac}}\)

https://doi.org/10.1351/goldbook.S05912
The value of the standard emf of a cell in which molecular hydrogen under standard pressure is oxidized to solvated protons at the left-hand electrode.
Source:
Green Book, 2nd ed., p. 59 (https://goldbook.iupac.org/files/pdf/green_book_2ed.pdf)