Affinity

Relationship by marriage (as between a husband and his wife's blood relations, or between a wife and her husband's blood relations); -- in contradistinction to consanguinity, or relationship by blood; -- followed by with, to, or between.

Kinship generally; close agreement; relation; conformity; resemblance; connection; as, the affinity of sounds, of colors, or of languages.

Companionship; acquaintance.

That attraction which takes place, at an insensible distance, between the heterogeneous particles of bodies, and unites them to form chemical compounds; chemism; chemical or elective affinity or attraction.

A relation between species or highe/ groups dependent on resemblance in the whole plan of structure, and indicating community of origin.

A superior spiritual relationship or attraction held to exist sometimes between persons, esp. persons of the opposite sex; also, the man or woman who exerts such psychical or spiritual attraction.

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

(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"; "James's affinity with Sam"

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"

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