the strength of the physical or chemical attraction between biological molecules, such as a receptor and its ligand

这种蛋白质对特定抗体具有很强的亲和性。

the capacity for different biological tissues, cells, or organisms to coexist or bond successfully without rejection

在植物嫁接过程中，接穗和砧木的亲和性是能否成活的关键因素。