| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 541 | Maeveen | Celtic | Nimble. | F | |
| 542 | Malcolm | Celtic | Servant of Saint Columba. | M | |
| 543 | Malvin | Celtic | Leader. | M | |
| 544 | Malvina | Celtic | Handmaiden. | F | |
| 545 | Malvyn | Celtic | Leader. | M | |
| 546 | Marella | Celtic | Shining sea. Variant of Muriel. | F | |
| 547 | Marilla | Celtic | Shining sea. Variant of Muriel. | F | |
| 548 | Mariner | Celtic | Lives by the sea. | M | |
| 549 | Marvin | Celtic | Lives by the sea. | M | |
| 550 | Marvina | Celtic | Renowned friend. Feminine of Marvin: Lives by the Sea. | F | |
| 551 | Marvyn | Celtic | Lives by the sea. | M | |
| 552 | Maureen | Celtic | Great. | F | |
| 553 | Mavelle | Celtic | Songbud. | F | |
| 554 | Mavie | Celtic | Songbud. | F | |
| 555 | Mavis | Celtic | Songbud. | F | |
| 556 | Meadghbh | Celtic | Nimble. | F | |
| 557 | Medb | Celtic | A mythical queen. | F | |
| 558 | Medredydd | Celtic | Mythical son of Medredydd. | M | |
| 559 | Melva | Celtic | Chief. Handmaiden. | F | |
| 560 | Melville | Celtic | Leader. | M | |