## Wikipedia - Full width at half maximum (it) half-width

of a band
https://doi.org/10.1351/goldbook.H02723
The full width of a spectral band at a height equal to half of the height at the band maximum. Also known as @F02565@. The dimension of band width should be either inverse length (wavenumbers) or inverse time (frequencies) so that the values give an indication of the energies. Note the hyphen in half-width. Half bandwidth has the meaning of half-width at half maximum.
Source:
PAC, 1996, 68, 2223. (Glossary of terms used in photochemistry (IUPAC Recommendations 1996)) on page 2245 [Terms] [Paper]