A chieftain is a leader, but chieftain implies a more specific, perhaps hereditary leadership, within a tribea tribe may be dozens to hundreds of people, larger than a band but not as large as a chiefdom; tribes are often associated with agriculture and animal domestication, though on a small scale; tribes may have a village or two with little bureaucracy and an informal political organization. There is a sense of an established or historically significant position. The role of chieftain often suggests a martial or warrior-like leadership style.
