What is Correspondence ?
Correspondence is (noun) 1. letters They had been carrying on a correspondence for years. She was told by her father to break off the correspondence. to be in correspondence with someone to write letters to someone and receive letters back I have been in correspondence with the company about a refund but with no success. 2. the fact that one thing matches or is similar to another There isn’t much correspondence between theory and practice.
source: Easier English, Student Dictionary Upper Intermediate Level