From Wiktionary, the free dictionary
mae gwaed yn dewach na dŵr
- blood is thicker than water
- Synonym: nes penelin nag arddwrn (literally “the elbow is nearer than the wrist”)
- D. G. Lewis, N. Lewis, editors (2005–present), “gwaed”, in Gweiadur: the Welsh-English Dictionary, Gwerin