https://doi.org/10.1351/goldbook.I03295
A chemical reaction, the principal product of which is isomeric with the principal reactant. An intramolecular isomerization that involves the breaking or making of bonds is a special case of a molecular rearrangement. Isomerization does not necessarily imply molecular rearrangement (e.g. in the case of the interconversion of conformational isomers).