polarization, \(\zeta\)

in electrochemistry
https://doi.org/10.1351/goldbook.P04713
The difference of the @E01956@ from the @C01357@. The symbol should not be used for @P04712@.
Source:
PAC, 1989, 61, 19. (Electrochemical corrosion nomenclature (Recommendations 1988)) on page 21 [Terms] [Paper]