ostler

n (formerly) man looking after horses at an inn; stableman （旧时）客栈的马夫.

oscillograph, oscilloscope, osier, osmosis, osmotic, osprey, osseous, ossification, ossified, ossify, ossilate, oste(o)-, ostensible, ostensibly, ostentation, ostentatious, ostentatiously, osteo-arthritis, osteopath, osteopathy, ostracism, ostracize, ostracize, ostracise, ostrich, OT, other, other from, other than, other-directed, other-worldly, others, otherwise, otiose, otter, ottoman, OU, oubliette, ouch, ought, ought to,