@shef Fediverse is actually a kind of nickname that has developed around certain projects. The term Fediverse already existed at a time when ActivityPub did not yet exist. At some point, the term probably expanded to include all servers that are connected to each other via ActivityPub. Some Fediverse projects also connect via other networks, such as ZOT or DFRN. But I think it's fair to say that nowadays ActivityPub is seen as the common denominator that defines the Fediverse. In principle, the term Fediverse is composed of “federation” and “universe.” The driving force behind this federated universe are people who use software with the ActivityPub protocol.