gwrthdorri

== Welsh == === Etymology === From gwrth- (“anti-”) +‎ torri (“to cut, to break”). === Pronunciation === IPA(key): /ɡʊrθˈdɔri/ === Verb === gwrthdorri (first-person singular present gwrthdorraf) (physics) to refract Synonyms: plygu, gwyro ==== Derived terms ==== gwrthdoriad (“refraction”) === Mutation === === Further reading === D. G. Lewis, N. Lewis, editors (2005–present), “gwrthdorri”, in Gweiadur: the Welsh–English Dictionary, Gwerin R. J. Thomas, G. A. Bevan, P. J. Donovan, A. Hawke, et al., editors (1950–present), “gwrthdorri”, in Geiriadur Prifysgol Cymru Online (in Welsh), University of Wales Centre for Advanced Welsh & Celtic Studies