intensity

https://doi.org/10.1351/goldbook.I03072
  1. The traditional term for photon flux, fluence rate, irradiance or radiant power (radiant flux). In terms of an object exposed to radiation, the term should now be used only for qualitative descriptions.
    Source:
    PAC, 1996, 68, 2223. 'Glossary of terms used in photochemistry (IUPAC Recommendations 1996)' on page 2248 (https://doi.org/10.1351/pac199668122223)
    See also:
    Green Book, 2nd ed., p. 31 (https://goldbook.iupac.org/files/pdf/green_book_2ed.pdf)
    Orange Book, 2nd ed., p. 228 (https://media.iupac.org/publications/analytical_compendium/)
    PAC, 1990, 62, 2167. 'Glossary of atmospheric chemistry terms (Recommendations 1990)' on page 2197 (https://doi.org/10.1351/pac199062112167)
  2. The magnitude of a particular feature in a spectrum.
    Source:
    PAC, 1996, 68, 2223. 'Glossary of terms used in photochemistry (IUPAC Recommendations 1996)' on page 2248 (https://doi.org/10.1351/pac199668122223)