Trishul, the trident, is one among the symbols of Shiva. Shiva in human form carries the Trishula. Origin of Trident as per Vishnu Purana is associated with Surya, the Sun God. It is believed that Trishul was carved out using matter from Sun.
Legend has that Surya married Samjna, the daughter of Vishwakarma. But Samjna was unhappy with her married life due to the unbearable heat of Surya. She complained to Vishwakarma, who agreed to solve the problem.
It is believed that Surya agreed to reduce his heat to accommodate Samjna and have a happy married life.
Another legend has that to reduce the heat of Surya, Vishwakarma removed a part of the burning matter from Surya – it said that Surya was grounded on a grinding machine for the purpose.
It is said that 1/8th of the heat of Surya was reduced.