Obayana
Nigerian: a king by the fire

Odell
Danish: an otter
Greek: a melody
(Dell, Ode, Odie, Odey)

Okapi
African: a giraffe-like animal with a long neck

Olaf
Danish or Norse: ancestor
(Olav, Ole, Olen, Olin, Olof)

Oleg
Russian: holy one
(Olezka)

Olin
Middl English: holly
(Olney)

Oliver
Latin: olive tree, which is a symbol of peace
(Ollie, Olivier)

Omar
Arabic: the firstborn son, or follower of the Prophet

Omri
Arabic: to live long, or to worship

Ona
British: ask tree
(Onny)

Oral
Latin: spoken word

Oren
Hebrew: cedar tree
Gaelic: pale face
(Oran, Orin, Orren, Orrin, Orryn, Oron, Orenthal)

Ori
Hebrew: he who is the light of my life

Orion
Greek: the hunter
French: from the Orient
(Orien, Orin, Orrin)

Orlando
Latin: man from the land of gold, or a variant of Roland
(Orland)

Orson
Latin: he who is life the bear
(Sonnie, Sonny, Urson)

Orton
Teutonic: wealthy one

Orville
Old French: the golden city
(Orv, Orval)

Osaze
Nigerian: favored one of God

Osborn
Old English: soldier of God
Scandinavian: the sacred bear
(Osborne, Osbourn, Osbourne, Ozzie, Ozzy)

Oscar
Scandinavian: spear of God
(Oskar, Ossie, Ozzie, Ozzy)

Osgood
Teutonic: divine creator, or maker of the heavens

Osmond
Old English: heavenly protection
(Esme, Osmand, Osmund, Ossie, Ozzie, Ozzy)

Oswald
Old English: God of power
(Ossy, Ossie, Oswaldo, Osvaldo, Ozzy, Wald, Waldo)

Otis
Greek: one who hears well
(Oates)

Oto
African: belonging to the Oto tribe

Otto
German: prosperous
(Odo, Othello, Otis)

Owen
Welsh: the fortunate one, or the well-born
(Bowen, Bowie, Ewan, Ewen, Evan, Owain)