- Biol. a similarity in appearance or structure of organisms belonging to different species or races
- Chem. an identity or close similarity in the crystalline form of substances usually containing different elements but having similar composition
- Math. a one-to-one correspondence between two mathematical systems, sets, etc. that preserves the basic operations, as the correspondence between binary numbers and decimal numbers, each a set of real numbers

Origin of isomorphism

from isomorphic + -ism