A trident is like a pitchfork in that it is a pole with prongs on the end. A trident has three prongs, no more, no less. Unlike the pitchfork, it is made as a weapon, usually being made of solid metal instead of mainly wood. It is essentially a three pronged spear. Other names for a trident are gig, leister, and trishul. The Trident Rats of Sampetra used tridents. Lasko Catta (The Castaway) used a trident also to kill Ublopp the rat.
Another famous user was Ungatt Trunn, who used it to fight Lord Brocktree in CH36 of Lord Brocktree.