Addition of zeros to a free induction decay or interferogram to decrease the frequency or wavenumber spacing between points in the Fourier-transformed spectrum.
Source:
PAC, 2021, 93, 647. 'Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)' on page 679 (https://doi.org/10.1515/pac-2019-0203)