If you're talking about small communities, then the most likely answer would be a village. Villages played an important role in the history of civilization. Villages were the first types of permament settlements people have built in the past. As such, they still represent the smallest permament type of settlement nowadays. In the early days however, they were vital for people to have a better chance of surviving and at first became to be because people started growing crops on the same spot, which sort of forced them to stay there for some time :)
