| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 561 | Melvin | Celtic | Leader. | M | |
| 562 | Melvina | Celtic | Handmaiden. | F | |
| 563 | Melvyn | Celtic | Leader. | M | |
| 564 | Menw | Celtic | Mythical a wizard. | M | |
| 565 | Meredith | Celtic | Protector of the sea. | F | |
| 566 | Meriel | Celtic | Variant of Muriel: Bright sea. | F | |
| 567 | Merlin | Celtic | From the hill over the sea. | M | |
| 568 | Merlyn | Celtic | From the hill over the sea. | M | |
| 569 | Merna | Celtic | Tender. | F | |
| 570 | Meryl | Celtic | Variant of Muriel: Bright sea. | F | |
| 571 | Mirna | Celtic | Tender. | F | |
| 572 | Moina | Celtic | Mild or tender. | F | |
| 573 | Moira | Celtic | Exceptional. | F | |
| 574 | Mor | Celtic | Exceptional. | F | |
| 575 | Moreen | Celtic | Great. | F | |
| 576 | Morfran | Celtic | Mythical ugly demon. | M | |
| 577 | Morgan | Celtic | Dweller of the sea. | F | |
| 578 | Morgan | Celtic | Lives by the sea. | M | |
| 579 | Morgana | Celtic | Dweller of the sea. | F | |
| 580 | Morgance | Celtic | Dweller of the sea. | F | |