In ac polarography, differential pulse polarography, derivative polarography, and similar techniques, the potential of the indicator electrode at which the summit current is attained.
Source:
PAC, 1985, 57, 1491. 'Recommended terms, symbols, and definitions for electroanalytical chemistry (Recommendations 1985)' on page 1503 (https://doi.org/10.1351/pac198557101491)