Merriam-Webster Collegiate Dictionary - correspondence

 noun  Date: 15th century  1.  a. the agreement of things with one another  b. a particular similarity  c. a relation between sets in which each member of one set is associated with one or more members of the other — compare function 5a  2.  a. communication by letters; also the letters exchanged  b. the news, information, or opinion contributed by a correspondent to a newspaper or periodical