Chapter I
What it means
The trishula, “three spears”, is the trident of Shiva. It shows his power to destroy, which in Hindu thought is not only an ending but the clearing away of ignorance that makes new creation possible.
The three prongs are given many meanings. Common ones are the three acts of creation, preservation and destruction; the three times, past, present and future; and the three gunas, the qualities that make up all of nature. In yoga traditions they are sometimes linked with three channels of subtle energy in the body.
Chapter II
Where it comes from
Shiva is shown holding a trident in Indian sculpture from the early centuries CE, and the weapon appears on coins of the period. The goddess Durga, who receives it from Shiva in the Devi Mahatmya, is shown piercing the buffalo demon with it in countless images.
Shaiva ascetics, the holy men devoted to Shiva, have long carried tridents, often with a small hourglass drum, the damaru, tied below the prongs.
Chapter III
Where you see it today
A tall trident often stands on top of or in the courtyard of a Shiva temple. Small brass tridents are offered at shrines, painted on walls and worn as pendants. The sign is popular as a tattoo and appears on the flags of some Hindu organisations.