| Maddock | Welsh | Meaning "generous." Notable people .. |  |  |
| Mallt | Welsh | Welsh form of Maud (powerful in bat.. | | |
| Malvern | Welsh | Which means "bare hill." | | |
| Margaret | Welsh | A borrowing from the English and th.. |  | |
| Marged | Welsh | Welsh form of Margaret (a pearl). S.. | | |
| Mari | Welsh | A Welsh form of Mary, Mair is an ev.. | | |
| Martha | Welsh | Derived from the Aramaic Martha (la.. | | |
| Maud | Welsh | Anglicized Norman contraction of Ma.. | | |
| Maurice | Welsh | A borrowing from the English, Mauri.. | | |
| Megan | Welsh | Pet form of Marged, which is a We.. | | |
| Meic | Welsh | Short form of Meical, the Welsh cog.. | | |
| Meical | Welsh | Welsh cognate of Michael (who is li.. | | |
| Meilyr | Welsh | Derived from the obsolete Old Celti.. | | |
| Meinwen | Welsh | Compound name composed of the Welsh.. | | |
| Meirion | Welsh | Welsh form of the Latin Marianus, a.. | | |
| Meiriona | Welsh | Feminine form of Meirion, the Welsh.. | | |
| Meirionwen | Welsh | Compound name composed of the name .. | | |
| Meredith | Welsh | Modern form of the Old Welsh Maredu.. | | |
| Mererid | Welsh | Welsh form of Margaret (a pearl). S.. |  | |
| Merfyn | Welsh | Popular name derived from the Old W.. | | |
| Merion | Welsh | A name signifying "from Merioneth, .. | | |
| Merlin | Welsh | Derived from the Welsh Myrddin, whi.. |  | |
| Mervyn | Welsh | Anglicized form of Merfyn (sea hill.. | | |
| Meurig | Welsh | A form of Maurice which means "mo.. | | |
| Meuriz | Welsh | Welsh form of Maurice (dark, swarth.. | | |
| Michael | Welsh | Derivative of the Hebrew mikha'el (.. | | |
| Mihangel | Welsh | Welsh form of Michael (who is like .. | | |
| Morgan | Welsh | Modern form of Morcant, an ancient .. | | |
| Morgan | Welsh | Modern form of Morcant, an ancient .. | | |
| Morgwen | Welsh | Compound name believed to be compos.. | | |
| Morwenna | Welsh | Old name of uncertain and debated d.. | | |
| Mostyn | Welsh | Transferred use of the Welsh place-.. | | |
| Myfanwy | Welsh | An old name of debated meaning, som.. | | |
| Myrddin | Welsh | Derived from the Primitive Celtic e.. | | |
| Nerys | Welsh | Modern coinage believed to be deriv.. | | |
