Lingam, generally referred to as Shiva Lingam is an embodiment of Hindu Lord Shiva. Lingam is a Sanskrit word which means “mark” or “symbol”. In physical world, Shiva Lingam is represented along with yoni, the female creative energy, as an elliptical structure on a circular base. It is believed in Hindu mythology that the lingam is a nirakara (formless) representation of God. It has neither the beginning nor the end. It signifies the infiniteness and supremacy of Lord Shiva over all the gods in Hindu Religion.
Shiv Purana states the importance of worshipping the Lingam. It states that Shiva is the masculine power and Parvati is the feminine power. The formless lingam is the base of universe and origin of the creation. The world we see is the reason of it. So lingam is considered to be the parent of creation in this universe. Therefore, Hindus revere and worship the lingam. Also according to the mythology, on the 14th day in the month of Phalguna, Shiva first transformed himself in the form of a Lingam. The day is celebrated as Mahashivaratri – the grand night of Shiva.
It is to be noted that most of the ancient Shiva temple has Lingam in the temple premises. On the other hand, there are temples where the lingam is the primary deity of the temple. Special puja and rituals are conducted according to Vedic practices plus rules and regulation. Mahashivarathri is the main festival of Shiva temples. It is celebrated in grand manner with devotion and dedication.