a covalent bond that links two chains of atoms, or two sections of one chain, in a polymeric molecule; the
cross-link is created by a third bond in a monomer unit in addition to the two bonds forming the polymeric chain; -- a
cross-link may be internal to a single chain, rather than between two otherwise unlinked chains;
as, ultraviolet irradiation creates cross-links between the two chains of a DNA double helix; many enzymes have cross-links formed by disulfide bonds; polystyrene resins have their porosity controlled by the proportion of cross-links. Called also
cross-linkage.
(Chem., Biochem.) Also: cross-linkage