osprey

n (type of) large fish-eating bird with a dark back and whitish head 鹗.

orthodox, orthodoxy, orthographic (also orthographical), orthographically, orthography, orthopaedic (also orthopedic), orthopaedics (also orthopedics), orthopaedist (also orthopedist), ortolan, oryx, OS, Oscar, oscillate, oscillation, oscillator, oscillograph, oscilloscope, osier, osmosis, osmotic, osseous, ossification, ossified, ossify, ossilate, oste(o)-, ostensible, ostensibly, ostentation, ostentatious, ostentatiously, osteo-arthritis, osteopath, osteopathy, ostler, ostracism, ostracize, ostracize, ostracise, ostrich, OT,