neidr y tomennydd

== Welsh == === Etymology === Literally, “snake of the dungheaps”. === Noun === neidr y tomenydd f (plural nadroedd y tomenydd or nadredd y tomenydd, not mutable) grass snake ==== Synonyms ==== neidr fraith neidr lwyd neidr y domen === Mutation === === Further reading === R. J. Thomas, G. A. Bevan, P. J. Donovan, A. Hawke, et al., editors (1950–present), “neidr y tomennydd”, in Geiriadur Prifysgol Cymru Online (in Welsh), University of Wales Centre for Advanced Welsh & Celtic Studies