English: house officer
Welsh: swyddog preswyl
Subject: Iechyd
English definition: HO. After 5 years at medical school students must spend one year in hospitals as House Officers.
Welsh definition: Ar ôl 5 mlynedd mewn ysgol feddygol rhaid i fyfyrwyr dreulio blwyddyn mewn ysbyty fel Swyddog Preswyl.