A graft copolymer is a macromolecule composed of a polymeric backbone of one constitutional composition with covalently attached side chains (grafts) of a chemically distinct polymer. The defining connectivity is a branching junction linking each graft to the main chain, so that the molecule is neither a linear block copolymer nor a statistical copolymer of the two repeat units along a single contour. Graft copolymers may be prepared by grafting-from (initiation from backbone-bound sites), grafting-onto (coupling of preformed chains to functional backbones), or grafting-through (copolymerization of macromonomers) strategies that all install covalent side-chain attachment ^[1]. Multigraft architectures with controlled graft number, spacing, and molecular weight illustrate the same structural class under well-defined synthetic constraints ^[2]. The concept requires covalent bonding between backbone and grafts; physical blends, interpolymer complexes, or merely adsorbed chains do not constitute graft copolymers. Comb polymers represent the densely grafted limiting case of this architecture.