Poseidon owns a trident.
The weapon of the Greek god Poseidon was the trident.
Trident
The Trident.
Zeus recieved a thunderbolt, Poseidon a trident and Hades a pitchfork
A trident and the power of the Ocean and water
His Trident.
Zeus' lightning bolt, Poseidon's trident and Hades' invisibility helmet.
Other than his godly power that he can probably summon without magical weapons, no. The Trident was his signature weapon, as was Zeus' master bolt.
Zeus's thunderbolts, Poseidon's trident, and Hades' Healm of Darkness all of which were used to win the War of the Titans.
Athena, Ares and Artemis are always depicted carrying weapons. Poseidon carries his trident about, which has more functions than just being a weapon. Similarly Zeus usually has his thunderbolts. The other gods can be armed when they like.
He makes many weapons in his forge. He made Aphrodite's Girdle and the magical net to catch Aphrodite cheating on him with the god of war, Ares. Most people believe that he made Zeus' lightning bolt, Poseidon's trident, and Hades' helmet, but actually the Polydectes (hundred handed ones) made them for the gods as thanks for freeing the Polydectes from Tartarus, where Uranus banished them. They then assisted the war for Olympus with the Titans and Zeus, Poseidon, and Hades used their new weapons to conquer the Titans.
Poseidon's Greek name was Poseidon. Poseidon's Roman name was Neptune.