correspondence

kɒrɪˈspɒnd(ə)ns

noun

a close similarity, connection, or equivalence.

there is a simple correspondence between the distance of a focused object from the eye and the size of its image on the retina

correlation,similarity,resemblance,comparability,compatibility,agreement,consistency,congruity,conformity,uniformity,harmony,affinity,accordance,accord,concurrence,coincidence,association,relationship,connection,interaction