1(Of a chemical reaction) having an order or a molecularity of more than one; involving more than one molecule in a single step.
2Consisting of or built up from more than one molecule.
3Of, relating to, or designating a film or layer more than one molecule in thickness. Of adsorption: characterized by the formation of such a layer.
4Consisting of macromolecules with similar polymeric structures but different molecular weights or different degrees of polmerization.
Late 19th century. From poly- + molecular, after German polymolekular.