Entries from:

PAC, 1985, 57, 105. Names, symbols, definitions and units of quantities in optical spectroscopy (Recommendations 1984), doi:10.1351/pac198557010105

absorptance,
decadic absorbance,
optical spectroscopy
spectral radiant power,
specular reflectance (reflection factor), in optical spectroscopy
total radiant power
wavelength,
wavenumber, ,