affinity
A natural attraction or feeling of kinship to a person or thing.
A family relationship through marriage of a relative (e.g. sister-in-law), as opposed to consanguinity (e.g. sister).
And married she was, thanks to the affinities of landed property!
A kinsman or kinswoman of a such relationship; one who is affinal.
The fact of and manner in which something is related to another.
Any romantic relationship.
A love interest; a paramour.
Any passionate love for something.
(taxonomy) Resemblances between biological populations, suggesting that they have a common origin, type or stock.
(geology) Structural resemblances between minerals; resemblances that suggest that they are of a common origin or type.
(chemistry) An attractive force between atoms, or groups of atoms, that contributes towards their forming bonds.
(medicine) The attraction between an antibody and an antigen
(computing) A tendency to keep a task running on the same processor in a symmetric multiprocessing operating system to reduce the frequency of cache misses.
(geometry) An automorphism of affine space.