Final answer:
The fingerprint region in the IR absorption spectrum refers to the range of 400 - 1400 cm^-1. It is unique to every molecule and can be used for positive identification.
Step-by-step explanation:
The fingerprint region in the IR absorption spectrum refers to the range of 400 - 1400 cm-1. It is called the fingerprint region because the pattern of absorbance peaks in this region is unique to every molecule, similar to a human fingerprint. Although it is difficult to identify specific functional groups in this region, comparing the unknown sample's data with the IR spectra of known standards can help in positive identification.