Starting with letter O
| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 21 | Octavius | Latin | Born eighth. Octavius was a Roman clan name, as well as the original name of Emperor Augustus (commonly known as Octavian). Traditionally, this name was given to the eighth child in a large family. | M | |
| 22 | Octavius | Shakespearean | Antony and Cleopatra'. Octavius Caesar, Roman triumvir. 'The Tragedy of Julius Caesar' Triumvir after Caesar's death, later Augustus Caesar, first emperor of Rome. | M | |
| 23 | Octe | Anglo-Saxon | A son of Hengist. | M | |
| 24 | Octha | ArthurianLegend | Enemy of Arthur. | M | |
| 25 | Ocumwhowurst | NativeAmerican | Yellow wolf (Cheyenne). | M | |
| 26 | Odakota | NativeAmerican | Friend (Sioux). | M | |
| 27 | Odam | English | Son in law. | M | |
| 28 | Oddleif | Norse | Point descendant. | M | |
| 29 | Oddvar | Norse | Pointable. | M | |
| 30 | Oded | Biblical | To sustain, hold or lift up. | M | |
| 31 | Oded | Hebrew | Encourages. | M | |
| 32 | Odhran | Irish | Pale green. | M | |
| 33 | Odion | Egyptian | Born of twins. | M | |
| 34 | Odo | German | Wealth. | M | |
| 35 | Odwolf | English | Wealthy wolf. | M | |
| 36 | Oedipus | Greek | Swollen foot. | M | |
| 37 | Oegelsby | English | Fearsome. | M | |
| 38 | Oeneus | Greek | King of Calydon. | M | |
| 39 | Oenomaus | Greek | Son of Ares. | M | |
| 40 | Ofydd | Welsh | Welsh form of Ovid 'a Roman poet'. | M | |