| Orrick | oak tree ... mainly used in the English language and ... irregularly used as a baby boy name ... |
| Ortiz | fortification ... language of origin is Spanish and it is used ... not frequently used as a baby boy name ... |
| Orton | short town; stag hill ... used predominantly in English ... derived from Old English and English ... |
| Osbert | bright god ... origin is Old English, and its use, English ... seldom used as a baby name for boys ... |
| Osborn | bear god ... has its origins in the Old Norse language ... uncommon as a baby name for boys ... |
| Osbourne | divine bear; bear god ... of Old Norse and English origin ... used mainly in English ... variant of Osborn ... |
| Osgood | divinely good ... of Old English origin and it is used ... unusual as a baby name for boys ... |
| Osiris | Egyptian god of the dead ... language of origin is Egyptian and it is used ... rare as a baby boy name ... |
| Osmond | a divine protector ... used mostly in English and its language ... not popular as a baby boy name ... |
| Ossian | little deer; small deer ... used predominantly in the English and ... variant of Oisin ... |
| Oswin | god, deity; friend ... origin is Old English, and its use, English and ... not in the top 1000 names ... |
| Otadan | plenty ... language of origin is Native American and it is ... not frequently used as a baby boy name ... |
| Othello | wealth, fortune ... has its origins in the Germanic language ... used largely in the English, French, ... |
| Ouray | the arrow ... of Native American origin and it is ... a rare baby boy name ... not listed in the top 1000 ... |
| Overton | riverside settlement ... largely used in the English language ... an unusual baby name for boys ... |
| Oxford | from the place where the oxen cross ... largely used in the English language ... |
| Pacey | of Easter ... primarily used in the English language, ... form of Pascal ... unusual as a baby name for boys ... |
| Packer | wool packer ... used predominantly in English and ... a seldom used baby name for boys ... |
| Pacumeni | ... primarily used in English and its ... not widely used as a baby name for ... not in the top 1000 names ... |
| Page | servant, helper ... largely used in the English language and ... represents the transferred use of the job ... |
