affinityyoudaoicibaDictYouDict
affinity: [14] The abstract notion of ‘relationship’ in affinity was originally a more concrete conception of a border. The word comes, via Old French afinite, from the Latin adjective affinis, which meant literally ‘bordering on something’. It was formed from the prefix ad- ‘to’ and the noun finis ‘border’ (from which English also gets finish, confine, and define).
=> confine, define, finish, paraffin, refine
affinity (n.)youdaoicibaDictYouDict
c. 1300, "relation by marriage" (as opposed to consanguinity), from Old French afinité (12c.), from Latin affinitatem (nominative affinitas) "neighborhood, relationship by marriage," noun of state from affinis "adjacent," also "kin by marriage," literally "bordering on," from ad- "to" (see ad-) + finis "a border, a boundary" (see finish (v.)). Used figuratively since c. 1600 of structural relationships in chemistry, philology, etc. Meaning "natural attraction" (as though by family) is from 1610s.