affinity

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

“basic dyes have an affinity for wool and silk”

A close connection marked by community of interests or similarity in nature or character.

“found a natural affinity with the immigrants”

(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 natural attraction or feeling of kinship.

“an affinity for politics”

“the mysterious affinity between them”

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

(immunology) the attraction between an antigen and an antibody.

Inherent resemblance between persons or things.