1.
1. A prefix or combining form, indicating identity, or equality; the same numerical value; as in isopod, isomorphous, isochromatic. Specif.
2. Applied to compounds of certain isomeric series in whose structure one carbon atom, at least, is connected with three other carbon atoms; contrasted with neo- and normal; as in isoparaffine; isopentane.
Origin: Gr. 'isos equal.
(29 Oct 1998)