Tribe is a word used to describe a group of individuals unified by a commonality in thoughts, actions, vocabulary or belief system according to the totem they subscribe to. Tribes are a kind of informal social arrangement. Bands are less complex, and Cheifdoms and States are more complex. In anthropology, a tribe is a "notional form of human social organization based on a set of smaller groups...having temporary or permanent political integration, and defined by traditions of common descent, language, culture, and ideology."
"The term originated in ancient Rome, where the word tribus denoted a division within the state. It later came into use as a way to describe the cultures encountered through European exploration."
iPhone users are a totem group whose actions, words and community is united by their use and subscription to the iPhone ecosystem. Some people may be part of the Mac tribe, and others part of the PC tribe. A person living in Portland, Oregon may have an wider tribal identity shared with the people of Portland, Oregon, followed by a smaller tribe of those in the same neighborhood, and their network of friends in similar socioeconomic groups who consume similar objects and have similar lifestyles.