The electronvolt (or eV) was a unit of energy. The electronvolt was also a factor in determining radiation density in terms of eV per cubic meter.
The hydrogen molecule has a "threshold" of 14.7 electronvolts. (VOY: "Relativity")
- Kiloelectronvolt = 1,000 electronvolts
A gamma scan revealed that the Crystalline Entity left behind a trail of antiprotons with a sharp spike at 10 keV. (TNG: "Silicon Avatar")
The tertiary subspace manifold, the home of a species of solanogen-based lifeforms, was located at a subspace energy level of 16.2 keV. (TNG: "Schisms")
- Megaelectronvolt = 1,000,000 electronvolts
In 2373, The Doctor purged Kes' body of chroniton radiation with antichroniton bursts increasing from a five second pulse at 10 MeVs, to five second pulse at 15 MeVs, before concluding at 20 MeVs. (VOY: "Before and After")