affinity
/əˈfɪnətɪ/noun
(pl. -ies)
1- a spontaneous or natural liking or sympathy for someone or something本性爱好, 同情心：
he had a special affinity with horses.
他对马有天生的喜爱。
1.1
- a similarity of characteristics suggesting a relationship, especially a resemblance in structure between animals, plants, or languages（尤指动物、植物、语言之间结构的）类同, 相似性。
1.2
- mass noun relationship, especially by marriage as opposed to blood ties（与血缘关系相对的）姻亲关系。
1.3
- chiefly Biochemistry the degree to which a substance tends to combine with another【主生化】亲和力, 亲和性。
词源
Middle English （in the sense 'relationship by marriage'）： via Old French from Latin affinitas, from affinis 'related' （literally 'bordering on'）， from ad- 'to'+finis 'border'.