This term should be applied only to sinusoidal phenomena; the term periodic voltage should be used for other wave forms.
See also: amplitude of alternating voltage
Source:
PAC, 1985, 57, 1491. 'Recommended terms, symbols, and definitions for electroanalytical chemistry (Recommendations 1985)' on page 1505 (https://doi.org/10.1351/pac198557101491)