Affinity

pl. Affinities

1. 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.

   Solomon made affinity with Pharaoh.

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

   There is a close affinity between imposture and credulity.

3. Companionship; acquaintance. [Obs.]

   About forty years past, I began a happy affinity with William Cranmer.

4. 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. (Chem.)
5. A relation between species or higher groups dependent on resemblance in the whole plan of structure, and indicating community of origin. (Nat. Hist.)
6. 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. (Spiritualism)