A katana is a Japanese sword best known for being used by samurais.
Illusions of Hikaru Sulu and a Samurai fought with Katanas after being discussed by James T. Kirk and Doctor Leonard McCoy. (TOS comic: "The Tree of Life, the Branches of Heaven")
Grauq owned a 23rd century katana, as well as a wakizashi. Iliana Ghemor took Grauq's katana from the Otamawan before she destroyed Grauq's ship, killing Grauq himself.
Ghemor later used Grauq's weapons against Savonigar, who managed to push it out of her grip with his own sword. It hit a mound of rock and disappeared. (DS9 novel: Warpath)