femtovolt noun1 •One quadrillionth (10⁻¹⁵) of a volt.Quantum fluctuations in superconductors created fluctuations that we could measure at a few femtovolts electrically, or magnetically at <10⁻¹⁵ Wb, or by temperature shifts of a few microKelvin. — 2001 formsfemtovolts
