noun (immunology) the attraction between an antigen and an antibody.
noun (anthropology) kinship by marriage or adoption.
noun (biology) state of relationship between organisms or groups of organisms resulting in resemblance in structure or structural parts.
— synonyms: phylogenetic_relation
noun a close connection marked by community of interests or similarity in nature or character.
— synonyms: kinship
noun the force attracting atoms to each other and binding them together in a molecule.
— synonyms: chemical_attraction
noun inherent resemblance between persons or things.