Congener is a term in chemistry that refers to one of many variants or configurations of a common chemical structure.
Source: GreenFacts
For example, polychlorinated biphenyls (PCBs) occur in 209 different forms, or congeners. Each congener has two or chlorine atoms located at specific sites on the PCB molecule.
Source: GreenFacts
Español: Congénere
Français: Congénère