two-dimensional nuclear magnetic resonance spectroscopy 

Synonym: 2-D NMR
https://doi.org/10.1351/goldbook.08439
Measurement method of nuclear magnetic resonance spectroscopy in which data are collected in two time domains: acquisition of the free induction decay (\(t_{2}\)) and a successively incremented delay (\(t_{1}\)).
Note:
The resulting data matrix is subjected to two successive Fourier transforms to produce a spectrum with two frequency axes, usually either chemical shift/chemical shift (correlation spectroscopy) or chemical shift/J-coupling (see J-resolved spectroscopy).
Source:
PAC, 2021, 93, 647. 'Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)' on page 710 (https://doi.org/10.1515/pac-2019-0203)