Different sociologists and anthropologists have given importance to different aspects or characteristics of tribal society and there is no universally accepted definition of a tribe. Tribe is a social group having many clans, nomadic bands and other sub groups living on a definite geographical area having separate language, separate and singular culture.
According to Imperial Gazetteer of India a tribe is a collection of families bearing a common name, speaking a common dialect, occupying or professing to occupy a common territory and is not usually endogamous though originally it might have been so.
According to Oxford Dictionary "A tribe is a group of people in a primitive or barbarious stage of development acknowledging the authority of a chief and usually regarding themselves as having a common ancestor.
D.N Majumdar defines tribe as a social group with territorial affiliation, endogamous with no specialization of functions ruled by tribal officers hereditary or otherwise, united in language or dialect recognizing social distance with other tribes or castes. Lucy Mair defines tribe as an independent political division of a population with a common culture. Gillin and Gillin considers any collection of pre-literate local group that occupies a common general territory speaks a common language and practices a common culture as a tribe.
According to Ralph Linton tribe is a group of bands occupying a contiguous territory or territories and having a feeling of unity deriving from numerous similarities in a culture,frequent contacts and a certain community of interests.
L.M Lewis believes that tribal societies are small in scale are restricted in the spatial and temporal range of their social, legal and political relations and possess a morality, a religion and worldview of corresponding dimensions. Characteristically too tribal languages are unwritten and hence the extent of communication both in time and space is inevitably narrow. At the same time tribal societies exhibit a remarkable economy of design and have a compactness and self-sufficiency lacking in modern society.
T.B Naik has given the following features of tribes in Indian context :
Naik argues that for a community to be a tribe it should possess all the above-mentioned characteristics and a very high level of acculturation with outside society debars it from being a tribe. Thus term usually denotes a social group bound together by kin and duty and associated with a particular territory.
Tribes in India are different from similar groups around the world. They are not homogenous group and within themselves they are at various stages of integration with the larger society. According to Andre Beteille, in India the encounters between tribe and civilization have taken place under historical conditions of a radically different sort. The co-existence of tribe and civilization and their mutual interaction go back to the beginnings of recorded history and earlier. Tribes have existed at the margins of Hindu civilization from time immemorial and these margins have always been vogue, uncertain and fluctuating. Hindu civilization acknowledged the distinction between tribe and caste in the distinction between two kinds of communities, Jana and jati, the one confined to the isolation of hills and forests, the other settled in villages and towns with a more elaborate division of labor. The transformation of tribes into castes has been documented by a large number of anthropologists and historians. The tribe as a mode of organization has always differed from the caste based mode of organization. But considered, as individual units tribes are not always easy to distinguish from castes particularly at the margins where the two modes of organization meet.
There are over 700 scheduled tribes notified under Article 342 of the Constitution of India. According to the 2015-16 Annual Report of the Ministry of Tribal Affairs the population of the Scheduled Tribes in the country is 10.45 crore which as per 2011 census constitutes 8.6% of the total population.