‘Cutting Spear’
Rhomgonyant, Rhongomiant, Rhongomyniad
Rhongomynyad is a legendary spear or lance closely associated with King Arthur.
It holds great significance in the Arthurian legends. It is sometimes depicted as an invincible weapon, possessing the power to pierce any defense. It is often connected with Arthur’s role as a defender of the realm.
It is thought that it equates with Ron, the lance or spear mentioned by Geoffrey of Monmouth.
Source
Culhwch and Olwen | Late 11th century