Caladcholg
The magical sword carried by Cú Chulainn, amongst others.
Its name derives from calad, ‘hard’, and bolg, ‘lightning’, and has been linguistically linked with Caladvwlch, the name given to Excalibur in the Mabinogion story of Culhwch and Olwen.
See also
Caledfwlch | The Legend of King Arthur
Source
Culhwch and Olwen | Late 11th century