rheol

== Welsh == === Etymology === From Middle Welsh reol, ryol, from Proto-Brythonic *rreɣol, from Latin rēgula (“rule”). === Pronunciation === IPA(key): /ˈr̥eː.ɔl/ === Noun === rheol f (plural rheolau) rule, regulation ==== Derived terms ==== === Mutation === === Further reading === D. G. Lewis, N. Lewis, editors (2005–present), “rheol”, in Gweiadur: the Welsh–English Dictionary, Gwerin R. J. Thomas, G. A. Bevan, P. J. Donovan, A. Hawke, et al., editors (1950–present), “rheol”, in Geiriadur Prifysgol Cymru Online (in Welsh), University of Wales Centre for Advanced Welsh & Celtic Studies