ornithologist

n expert in ornithology 鸟类学家.

orientate, orientation, orienteering, orifice, origin, original, original sin, originality, originally, originate, originator, oriole, ormolu, ornament, ornamental, ornamentation, ornate, ornately, ornateness, ornithological, ornithology, orotund, orphan, orphanage, orris-root, orth(o)-, orthodontic, orthodontics, orthodontist, orthodox, orthodoxy, orthographic (also orthographical), orthographically, orthography, orthopaedic (also orthopedic), orthopaedics (also orthopedics), orthopaedist (also orthopedist), ortolan, oryx, OS,