A connection is a relationship between two things, people, or groups.
What is the word for a relationship between two things?
correlation. / (ˌkɒrɪˈleɪʃən) / noun. a mutual or reciprocal relationship between two or more things.
What does it mean to relate two things?
The verb relate means "to make a connection." If you can relate to someone's story, something like that has happened to you. Relate also means "to give an account of something verbally," like relating details of your trip to Sweden.