affinity

the force attracting atoms to each other and binding them together in a molecule

• “basic dyes have an affinity for wool and silk”

(immunology) the attraction between an antigen and an antibody

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”

inherent resemblance between persons or things

a natural attraction or feeling of kinship

• “an affinity for politics”
• “the mysterious affinity between them”
• “James”