n. (pl. -ies) 1 (often foll. by between, or disp. to, for) a spontaneous or natural liking for or attraction to a person or thing. 2 relationship, esp. by marriage. 3 resemblance in structure between animals, plants, or languages. 4 a similarity of characters suggesting a relationship. 5 Chem. the tendency of certain substances to combine with others.
[ ME f. OF afinité f. L affinitas -tatis f. affinis related, lit. bordering on (as AD- + finis border) ]