(n)affinity, phylogenetic relation(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”
(n)affinity, kinshipa 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”
(n)affinity, chemical attractionthe force attracting atoms to each other and binding them together in a molecule“basic dyes have an affinity for wool and silk”