Hindu denominations, sampradayas, traditions, movements, and sects are traditions and sub-traditions within Hinduism centered on one or more gods or goddesses, such as Vishnu, Shiva, Shakti and so on. The term sampradaya is used for branches with a particular founder-guru with a particular philosophy.
Hinduism has no central doctrinal authority and many practising Hindus do not claim to belong to any particular denomination or tradition. Four major traditions are, however, used in scholarly studies: Vaishnavism, Shaivism, Shaktism and Smartism. These are sometimes referred to as the denominations of Hinduism, and they differ in the primary deity at the centre of the tradition. A notable feature of Hindu denominations is that they do not deny other concepts of the divine or deity, and often celebrate the other as henotheistic equivalent. The denominations of Hinduism, states Lipner, are unlike those found in major religions of the world, because Hindu denominations are fuzzy with individuals practising more than one, and he suggests the term "Hindu polycentrism".
Although Hinduism contains many denominations and philosophies, it is linked by shared concepts, recognisable rituals, cosmology, shared textual resources, and the questioning of authority.
The word Hindu is an exonym. This word Hindu is derived from the Indo-Aryan and Sanskrit word Sindhu, which means "a large body of water", covering "river, ocean". It was used as the name of the Indus River and also referred to its tributaries. The actual term 'hindu' first occurs, states Gavin Flood, as "a Persian geographical term for the people who lived beyond the river Indus (Sanskrit: Sindhu)". Hindus are persons who regard themselves as culturally, ethnically, or religiously adhering to aspects of Hinduism. Historically, the term has also been used as a geographical, cultural, and later religious identifier for people living in the Indian subcontinent. In the 18th century, European merchants and colonists began to refer to the followers of Indian religions collectively as Hindus until about mid 20th century.