In the Beer Lambert Law (equation 3) the term IT/Io is called transmittance. This form of spectroscopy has a setup similar to the one used for Absorption. Reflectance spectroscopy is the study of light as a function of wavelength that has been reflected or scattered from a solid, liquid, or gas.
Definition of metadata: Data that serves to provide context or additional information about other data. For example, information about the title, subject, author, typeface, enhancements, and size of the data file of a ...
Metadata is data that describes other data. Metadata summarizes basic information about data, which can make finding and working with particular instances of data easier. For example, author, date created and date modified and file size are examples of very basic document metadata.