affinity

(immunology) the attraction between an antigen and an antibody

(anthropology) kinship by marriage or adoption; not a blood relationship

(biology) state of relationship between organisms or groups of organisms resulting in resemblance in structure or structural parts; "in anatomical structure prehistoric man shows close affinity with modern humans"

a close connection marked by community of interests or similarity in nature or character; "found a natural affinity with the immigrants"; "felt a deep kinship with the other students"; "anthropology's kinship with the humanities"

the force attracting atoms to each other and binding them together in a molecule; "basic dyes have an affinity for wool and silk"

inherent resemblance between persons or things

a natural attraction or feeling of kinship; "an affinity for politics"; "the mysterious affinity between them"; "James's affinity with Sam"