Type Word Usage Old Celtic (Hypothetical) Meaning & History Celtic word meaning "sea" [1]. Related ItemsDetails Other Languages & Culturesmuir(Old Irish) mor(Old Welsh) Given Name DescendantsMerlin(Arthurian Cycle) Marlin, Marlyn, Merlin, Merlyn(English) Myrddin(Welsh) Myrddin(Welsh Mythology) Place Name DescendantMoridunum(Brythonic) Same Spellingmori 1 Sources & References Matasović, Ranko. Etymological Dictionary of Proto-Celtic. Brill, 2009, page 277.