Menachot 24a Connected or Joined - כלי מצרף תנן

When two things (or individuals, or communities) are connected, each retains their own separate identity. Their chommer remains separate but together they create a different tzura. When they are joined rather than connected, both are part of something new and different from each of them. Not only their tzura but even their chomer is changed. One connects through transaction. One joins through investment. Source Sheet