correspondence
//ˌkɒr.ɪˈspɒn.dəns//
Noun
correspondenceSingular
correspondencesPlural
1
Communication by exchanging letters, emails, or other written messages.
We have been in correspondence for over a year.
2
The letters, emails, or other written messages exchanged between people.
I found a box of old correspondence between my grandparents.
3
A close similarity, connection, or equivalence between two or more things.
There is a close correspondence between the two reports.