/ˈoʊpən ˈprɪzn/ – Phrase
Definition: (Anh) trại giam mở (không có người gác).
A more thorough explanation: An open prison, also known as a minimum-security prison, is a correctional facility where inmates are allowed greater freedom of movement and are often permitted to leave the prison grounds for work, education, or other approved activities. Inmates in open prisons typically have lower security classifications and are considered to be at lower risk of escape or posing a threat to public safety.
Example: In an open prison, inmates are allowed to leave the facility during the day for work or other approved activities, but must return at night.