| Name | Meaning | Gender | Origin |
|---|
| Nicky | Abbreviation of Nicholas. Mythological Nike was Greek goddess of victory and root origin of Nicholas.
| Female | |
| Nico | people of victory | Male | Greek |
| Nikita | unconquered | Male | Russian |
| Nitro | Short for Nitroglycerin a highly explosive liquid. | Male | |
| Oakley | from the oak meadow | Male | 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 |
| Olly | | Unisex | |
| 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 |
| Opie | | Unisex | |
| Orion | Son of Fire
| Male | Greek |
| Orlando | Famous land
| Male | Italian |
| Oscar | God's spear.
| Male | English |
| Otto | Born eighth or wealthy
| Male | |
| Ozzie | Strong
| Male | Short |
| Pamela | honeyed | Female | English |
| Parker | cultivated land | Male | English |
| Paxton | From the peaceful farm
| Male | Latin |
| Phoenix | Mystical Bird, Purple
| Male | Greek |
| Phoenix | Mystical Bird, Purple
| Male | Greek |
| Pierce | rock | Male | English |
| Pierce | rock | Unisex | |
| Pilot | | Male | |
| Piney | | Unisex | Hebrew |