gwyrddfaen

== Welsh == === Etymology === From gwyrdd (“green”) +‎ maen (“stone”). === Pronunciation === (North Wales) IPA(key): /ˈɡwərðvaɨ̯n/ (South Wales) IPA(key): /ˈɡwərðvai̯n/ === Noun === gwyrddfaen m (plural gwyrddfeini) greenstone === Mutation === === References === R. J. Thomas, G. A. Bevan, P. J. Donovan, A. Hawke, et al., editors (1950–present), “gwyrddfaen”, in Geiriadur Prifysgol Cymru Online (in Welsh), University of Wales Centre for Advanced Welsh & Celtic Studies