A prison officer (UK and Ireland, and the official English title in Denmark, Finland, and Sweden), also known as corrections officer (New Zealand, US), correctional officer (Australia, Canada, Jamaica, and US), detention officer (US) or penal officer (US), is a person responsible for the supervision, safety, and security of prisoners in a prison, jail, or similar form of secure custody. Historically, terms such as jailer (also spelled jailor or gaoler), jail guard, prison guard, and turnkey have also been used. (source)