Oadal: tree
Obi (African): Male. "heart"
Obsidian: stone
Oca: plant
Ochna: tree
Ocote: tree
Octavia (Latin): Female. "eight"
Ohia: tree
Okote: tree
Olea: tree
Olive: tree
Olivine: stone
Olona: plant
Olumide (African): Male. "God arrives"
Olumjumi (African): Male. "given by God"
Onno (Japanese): "workman's meadow"
Onyksi (Finnish): "onyx"
Orabela (Esperanto): Female. "golden-beautiful"
Ore: stone
Orestes (Greek): Male. "mountain"
Orion (Greek): Male. "Hunter"
Orlitza (Russian): Female. "eagle"
Owen (Celtic): Male. "lamb, young warrior"