monoclonal UK /ˌmɒn.əˈkləʊ.nəl/US /ˌmɑn.əˈkloʊ.nəl/adjective 1noun 1forms 1 adjective1 •genetically engineered from a single clone; used especially of a protein or antibody noun1 •something produced from a single clone, especially a monoclonal antibody formsmonoclonals