Short answers, pulled from the story.
The word Hindu is an exonym derived from the Sanskrit word Sindhu, the name of the Indus River, and the region of the lower Indus basin. In the 6th century BCE, the inscription of Darius I mentioned Hindush as one of his provinces, and the term Hindu in these ancient records was purely geographical. It referred to the land beyond the Indus, and by extension, all the people who lived on this land.
The earliest known records of Hindu with connotations of religion appear in the 7th-century CE Chinese text Record of the Western Regions by Xuanzang. By the 14th century, the term Hindu appeared in Persian, Sanskrit, and Prakrit texts within India, often used in comparative contexts to contrast with Muslims or Turks. The first Indian to use Hinduism may have been Raja Ram Mohan Roy in 1816-17.
Classical Hindu thought accepts four proper goals or aims of human life, known as Purusharthas Dharma, Artha, Kama and Moksha. Dharma refers to moral duties and righteousness, Artha to the pursuit of means and resources for a fulfilling life, Kama to sensory and emotional pleasure, and Moksha to liberation from suffering and the cycle of rebirth.
Shruti primarily refers to the Vedas, which form the earliest record of the Hindu scriptures, and are regarded as eternal truths revealed to the ancient sages rishis. The most notable of the Smritis are the Hindu epics and the Puranas, which include the Mahabharata and the Ramayana. The Bhagavad Gita is an integral part of the Mahabharata and one of the most popular sacred texts of Hinduism.
Scholars regard Hinduism as a fusion or synthesis of Brahmanical orthopraxy with various Indian cultures, having diverse roots and no specific founder. This Hindu synthesis emerged after the Vedic period, between 800 and 200 BCE, and in the period of the second urbanisation and the early classical period of Hinduism when the epics and the first Puranas were composed.
Bal Gangadhar Tilak gave the following definition in Gita Rahasya 1915: Acceptance of the Vedas with reverence; recognition of the fact that the means or ways to salvation are diverse; and realization of the truth that the number of gods to be worshipped is large. It was quoted by the Indian Supreme Court in 1966, and again in 1995, as an adequate and satisfactory definition, and is still the legal definition of a Hindu today.