Gladius

A gladius was a Roman sword.

On the planet 892-IV, the gladius was used by the police and guards as a side weapon. It was also used in gladiatorial combat and executions. Captain James T. Kirk was almost killed by one. 

On the transport asteroid Yonada, the Fabrini soldiers were armed with swords that resembled imitation gladii. 

Later in 2268 when the Beta XII-A entity altered the USS Enterprise (NCC-1701), and gave everyone primitive weapons, various versions of gladii were created. Pavel Chekov was given a proper one of these, and later, Kirk and Kang faced each other with "imitation" ones.