Tawi'Yan

From Memory Alpha, the free Star Trek reference

Tawi'Yan is a term in Klingonese meaning "sword-bearer". In a Klingon wedding the Tawi'Yan was their equivalent of Earth's best man.

Alexander Rozhenko acted as the Tawi'Yan in his father Worf's wedding to Jadzia Dax in 2374. (DS9: "You Are Cordially Invited")