Two entries with the name Glessig.
Glessig
Glesing, Glessic
The sword wielded by Arthur’s warrior Cyfwlch in Culhwch and Olwen.
Source
Culhwch and Olwen | Late 11th century
Glessig
Glesing, Glessic
In Culhwch, Glessic is also said to be the name of a dog.
Source
Culhwch and Olwen | Late 11th century
See also
Glas | The Legend of King Arthur
Gleisyad | The Legend of King Arthur