rhyferthwy

== Welsh == === Etymology === Inherited from Middle Welsh ryverthwy, from Proto-Celtic *ɸrobert-. === Noun === rhyferthwy m or f (plural rhyferthwyau or rhyferthwyon) tempest Synonyms: storm, tymestl hurricane Synonym: corwynt torrent, deluge Synonyms: rhyferthi, dylif, dilyw, llifogydd, gorllanw === Mutation === === Further reading === D. G. Lewis, N. Lewis, editors (2005–present), “rhyferthwy”, in Gweiadur: the Welsh–English Dictionary, Gwerin R. J. Thomas, G. A. Bevan, P. J. Donovan, A. Hawke, et al., editors (1950–present), “rhyferthwy”, in Geiriadur Prifysgol Cymru Online (in Welsh), University of Wales Centre for Advanced Welsh & Celtic Studies