Definition of overvoltage in US English:

overvoltage

noun

  • 1Chemistry. The extra potential above the value for theoretical, reversible conditions which must be applied to an electrolytic cell to liberate a substance at an electrode in practical, irreversible conditions.

  • 2A voltage in excess of some threshold value, or of that which is normal, safe, or allowed for.

Origin

Early 20th century. From over- + voltage. Compare German Überspannung.