noun[mass noun] Chemistry
The common, stable isotope of hydrogen, as distinct from deuterium and tritium.
More example sentences
- The three isotopes are sometimes known by the names of protium, deuterium, and tritium.
- His hypothesis was that the lighter and more abundant protium isotope would evaporate more quickly than the heavier hydrogen - 2 isotope.
1930s: modern Latin, from Greek prōtos 'first'.
Definition of protium in:
- The US English dictionary