Linked from
The 13 pages that link to Absorbance, each with the reason it gives.
Absorption spectrumBroader topic: Absorption spectra commonly plot absorbance against wavelength.
TransmittanceRelated: Absorbance and transmittance are related by a logarithmic conversion.
Optical filterRelated: Absorbance describes the attenuation mechanism used by colored-glass filters.
Absorption bandRelated: Absorbance quantifies the height of a band in many spectra.