| Name | Meaning | Gender | Origin |
|---|
| Morgan | Uncertain, perhaps bright sea | Female | Welsh |
| Morgana | Uncertain, perhaps bright sea | Female | Welsh |
| Morgance | Dweller Of The Sea | Female | English |
| Morgandy | Little One From The Edge Of The Sea | Female | Celtic |
| Morgen | Sea-born | Female | Welsh |
| Moriarty | Expert Seaman | Male | English |
| Mortimer | Dead sea | Male | French |
| Morty | Dead sea | Male | French |
| Morven | Lives By The Sea | Male | English |
| Mukluk | A soft boot worn by Eskimos, often lined with fur and usually made of sealskin or reindeer skin | Both | English |
| Murdock | Sea | Male | Gaelic |
| Muriel | Bright as the sea | Female | Gaelic |
| Murphy | Sea warrior | Male | Gaelic |
| Murray | Man of the sea | Male | Gaelic |
| Nashaly | Born During Rainy Season | Female | African |
| Nasiche | Given life during the locust season | Female | African |
| Neptune | God of the sea | Unisex | Latin |
| Nerin | Nereid, One From The Sea | Female | Greek |
| Nerissa | Sea sprite | Female | Greek |
| Oki | Open sea | Female | Japanese |
| Onida | The One Searched For | Female | English |
| Pelagia | Of the Sea | Female | Greek |
| Ritu | Clock (time or season) | Female | Indian |
| Romey | Sea dew | Unisex | Latin |
| Romy | Sea dew | Unisex | Latin |
| Ronan | Little seal | Male | Gaelic |
| Ronin | Little seal | Male | Gaelic |
| Roseanne | Rose | Female | Latin |
| Rosemarie | Sea dew | Female | Latin |
| Rosemary | Sea dew | Female | Latin |