Proper noun
Dyserth
A village and community in Denbighshire, Wales; historically in Flintshire (OS grid ref SJ0579).
By early December, Llywelyn controlled all of Gwynedd Is Conwy apart from the royal castles at Dyserth and Dnoredudd as a reward for his support and dispossessing his brother-in-law, Rhys Fychan, who supported the king. Source: Internet