1. Without fault or error
   "faultless logic"
   - immaculate, impeccable

See also: faultlessly, perfect

• genus Orcinus
• genus Oreamnos
• genus Orectolobus
• genus Oreopteris
• genus Oreortyx
• genus Origanum
• genus Oriolus
• genus Orites
• genus Ormosia
• genus Ornithogalum
• genus Ornithorhynchus
• genus Orontium
• genus Ortalis
• genus Orthilia
• genus Orthopristis
• genus Orthotomus
• genus Orycteropus
• genus Oryctolagus
• genus Oryx
• genus Oryza
• genus Oryzomys
• genus Oryzopsis
• genus Osmanthus
• genus Osmerus
• genus Osmunda