1Tautomerism or tautomeric change, regarded as occurring through the detachment of an ion from the molecule concerned followed by a redistribution of the charge in the resulting molecular ion and reattachment of the ion to a different part of it.
2The ordering of particles in a gel that results when an electrolyte is added to a colloidal suspension.
1920s. From iono- + -tropy.
= inotropy .