orbis, is, m., circle; orbis terrae or terrārum, the world.
orbitās, ātis [orbus, destitute], f., bereavement, orphanage.
Orchadēs, um, pl. f., a group of islands north of Scotland, now Orkney Islands.
ōrdinārius, a, um [ōrdinō], adj., of order, usual, regular, ordinary.
ōrdinō, āre, āvī, ātus [ōrdō], to arrange, regulate.
ōrdō, inis, f., an order, rank, row.
Orestēs, is, m., Cn. Aufidius Orestes, consul 73 B.C.
Oriēns, entis [orior], m. (sc. sōl), the rising sun, the East, the Orient.
orīgō, inis [orior], f., an origin, source, pedigree.
orior, īrī, ortus sum, to rise, begin, spring from.