The Collaborative International Dictionary of English v.0.48:
macromolecule \mac`ro*mol"e*cule\, n. (Chem., Biochem.) A very large molecule, especially a polymer having from hundreds to many thousands of atoms, such as DNA, RNA, protein, polysaccharide, polyethylene, polycarbonate, etc. [PJC]WordNet (r) 3.0 (2006):
macromolecule n 1: any very large complex molecule; found only in plants and animals [syn: macromolecule, supermolecule]