Trishul, the Trident, is one of the most popular symbols associated with Lord Shiva and Goddess Durga. In the usual interpretation, it is a weapon used by Lord Shiva and Goddess Durga for the restoration of Dharma. But the Trishul has a deeper symbolic meaning.
Trishul is always held by Lord Shiva or it is depicted as rooted on the ground near Shiva. The trident is also part of the iconography of Goddess Durga killing demon Mahisha – the Mahishasura Mardana. The Goddess is depicted as killing the demon with the Trishul.
The Trishul symbolizes the balance of the three forces of preservation, creation and destruction.
There are also two other interpretations of the Trishul symbol.
One is that it represents the three aspects of consciousness – cognition, conation and affection.
Another is that it represents the three Gunas or Praktriti – Sattva, Rajas and Tamas.