Synonyms for Affinity (same or very similar meaning)
WordNet sense 1 ((biology) state of relationship between organisms or groups of organisms resulting in resemblance in structure or structural parts):
phylogenetic relation
WordNet sense 2 (a close connection marked by community of interests or similarity in nature or character):
kinship
WordNet sense 3 (the force attracting atoms to each other and binding them together in a molecule):
chemical attraction
From the ODE community, based on WordNet
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