full-width at half-maximum

1. Pertaining to a measure of the extent of a function, given by the difference between the two extreme values of the independent variable at which the dependent variable is equal to half of its maximum value. Common abbreviationFWHM.Note: Full-width at half-maximum (FWHM) usually pertains to the duration of pulse waveforms, the spectral composition of emission or absorption lines, and the angular or spatial extent of radiation patterns. “Full-duration at half-maximum” is preferred when the independent variable is time. 2. Pertaining to the range over which a property of a variable has a value greater than 50% of its maximum value. Note: Full-width at half-maximum (FWHM) pertains to (a) characteristics, such as radiation patterns, optical pulse durations, spectral widths, spectral line widths, beam diameters, beam-widths, and beam divergences and (b) variables, such as wavelength, voltage, power, and current. Synonymfull-width half-maximum. See alsoabsorption, bandwidth, beam diameter,...