| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 701 | Merwyn | Welsh | Form of Merlin. | M | |
| 702 | Meurig | Welsh | Dark-skinned; A Moor. Form of Morris. | M | |
| 703 | Mihangel | Welsh | Welsh form of Michael 'God like'. | M | |
| 704 | Mil | Welsh | Legendary son of Dugum. | M | |
| 705 | Modlen | Welsh | Welsh form of Magdalene: tower. | F | |
| 706 | Moesen | Welsh | Welsh form of Moses 'from the water'. | M | |
| 707 | Morcan | Welsh | Bright sea. | F | |
| 708 | Morcan | Welsh | Dwells near the sea. | M | |
| 709 | Morcar | Welsh | Dwells near the sea. | M | |
| 710 | Mordwywr | Welsh | Sailor. | M | |
| 711 | Moren | Welsh | Legendary son of Iaen. | M | |
| 712 | Morgaine | Welsh | Bright sea. | F | |
| 713 | Morgan | Welsh | Bright sea. From the shore of the sea. Morgan le Fay was sorceress and sister to King Arthur in Arthurian legend. | F | |
| 714 | Morgan | Welsh | Bright sea. Dwells near the sea. | M | |
| 715 | Morgana | Welsh | From the shore of the sea. | F | |
| 716 | Morgann | Welsh | Bright sea. | F | |
| 717 | Morgannwg | Welsh | From Glamorgan. | M | |
| 718 | Morgant | Welsh | From the shore of the sea. | F | |
| 719 | Morgen | Welsh | Of the sea. Surname. | M | |
| 720 | Morthwyl | Welsh | Hammer. | M | |