[in.clu.sion] n [L inclusion-, inclusio, fr. includere] (1600) 1: the act of including: the state of being included
2: something that is included: as a: a gaseous, liquid, or solid foreign body enclosed in a mass (as of a mineral) b: a passive usu. temporary product of cell activity (as a starch grain) within the cytoplasm or nucleus
3: a relation between two classes that exists when all members of the first are also members of the second--compare membership 3