join

If someone joins two or more things, they bring them together.

Example: Their lives were joined.

If someone joins someone else, they do something together.

Example: I will join you on your walk.

If someone joins a club, school, etc. they become a member.

Example: Would you like to join our club?

If someone joins two or more things, they make a connection between them.

Example: The new building is joined to the school by a short hallway.