affinity in WordNet English dictionary

1. inherent resemblance between persons or things
   affinity 
   
2. a natural attraction or feeling of kinship
   "an affinity for politics"; "the mysterious affinity between them"; "James's affinity with Sam"
   affinity 
   
3. the force attracting atoms to each other and binding them together in a molecule
   "basic dyes have an affinity for wool and silk"
   affinity  chemical attraction 
   
4. (immunology) the attraction between an antigen and an antibody
   affinity 
   
5. (anthropology) kinship by marriage or adoption; not a blood relationship
   affinity 
   
6. (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"
   affinity  phylogenetic relation 
   
7. 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"
   affinity  kinship