(chemistry) two or more atoms bound together as a single unit and forming part of a molecule(noun)
WordNet. Princeton University. 2010.
Use "chemical group" in a sentence
"His work included investigations on the replacement of one chemical group by another in minerals; the discovery of the amorphic state of several bodies, the artificial production of ultramarine and improvements in the dyeing industry, in the manufacture of beet-root sugar and in brewing."