macromolecule definition
A molecule containing a very large number of atoms, such as a protein, nucleic acid, or synthetic polymer. Example sentences. 1  During these reactions, they are chemically linked forming macromolecules, or polymers, which have large molecular weights. molecule containing a very large number of atoms, such as a protein, nucleic acid, or synthetic polymer. Example sentences. 1  During these reactions, they are chemically linked forming macromolecules, or polymers, which have large molecular weights.