| Name | Meaning | Gender | Origin |
|---|
| Moose | Largest member of the deer family. Moose have heavy brown bodies with humped shoulders and broad antlers. | Unisex | |
| Mugsy | | Unisex | Hebrew |
| Mystic | | Unisex | Hebrew |
| Neo | from The Matrix movies | Male | Latin |
| Nick | Variation of Dominic, belonging to the Lord | Male | English |
| Nicky | Abbreviation of Nicholas. Mythological Nike was Greek goddess of victory and root origin of Nicholas.
| Female | |
| Nitro | Short for Nitroglycerin a highly explosive liquid. | Male | |
| Nutmeg | | Male | |
| Nyx | Greek goddess of night | Female | Greek |
| Ody | | Unisex | |
| Olive | kind one; olive tree, peace. Symbol of peace. A small oval fruit. | Female | English |
| Oliver | The olive tree. The biblical olive tree symbolizes fruitfulness and beauty and dignity. Extending an olive branch signifies an offer of peace.
| Male | Latin |
| Omar | first son, disciple; gifted speaker; famous | Male | Arabic |
| ONeil | | Unisex | Hebrew |
| Onyx | A gemstone with bands of different colours. | Male | |
| Opal | Australian gemstone of remarkable colours, usually red, blue or green | Female | Sanskrit |
| Opal | Australian gemstone of remarkable colours, usually red, blue or green | Female | Sanskrit |
| Oreo | American cookie brand consisting of two chocolate wafers with white cream filling. | Male | |
| Oreo | American cookie brand consisting of two chocolate wafers with white cream filling. | Male | |
| Ozzie | Strong
| Male | Short |
| Pain | | Unisex | Hebrew |
| Panther | A black leopard | Male | |
| Patches | | Male | |
| Pebbles | after the character in 'The Flintstones' cartoons | Male | |
| Penny | Greek, weaver | Female | English |