The isomerization by which tautomers are interconverted. It is a heterolytic molecular rearrangement and is frequently very rapid.
See: tautomerism
Source:
PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1172 (https://doi.org/10.1351/pac199466051077)