affinity

Short definition from Wiktionary

Noun

1. 1
   A natural attraction or feeling of kinship to a person or thing.
2. 2
   A family relationship through marriage of a relative (e.g. sister-in-law), as opposed to consanguinity (e.g. sister).
3. 3
   A kinsman or kinswoman of a such relationship; one who is affinal.
4. 4
   The fact of and manner in which something is related to another.
5. 5
   Any romantic relationship.
6. 6
   A love interest; a paramour.
7. 7
   Any passionate love for something.
8. 8
   Resemblances between biological populations, suggesting that they have a common origin, type or stock.
9. 9
   Structural resemblances between minerals; resemblances that suggest that they are of a common origin or type.
10. 10
    An attractive force between atoms, or groups of atoms, that contributes towards their forming bonds.
11. 11
    The attraction between an antibody and an antigen
12. 12
    A tendency to keep a task running on the same processor in a symmetric multiprocessing operating system to reduce the frequency of cache misses.
13. 13
    An automorphism of affine space.