5. Why do we wear marks (tilak, pottu and the like) on the forehead?
The tilak or pottu invokes a feeling of sanctity in the wearer and others. It is recognized as a religious mark. Its form and colour vary according to one's caste, religious sect or the form of the Lord worshipped. In earlier times, the four castes (based on varna or colour) - Brahmana, Kshatriya, Vaishya and Sudra - applied marks differently. The brahmin applied a white chandan mark signifying purity, as his profession was of a priestly or academic nature. The kshatriya applied a red kumkum mark signifying valour as he belonged to warrior races. The vaishya wore a yellow kesar or turmeric mark signifying prosperity as he was a businessman or trader devoted to creation of wealth. The sudra applied a black bhasma, kasturi or charcoal mark signifying service as he supported the work of the other three divisions. Also Vishnu worshippers apply a chandan tilak of the shape of " U ," Shiva worshippers a tripundra of bhasma, Devi worshippers a red dot of kumkum and so on). T...