拘留 (jū liú) is the formal legal term for detaining a person by police or authorities, typically for a short period (e.g., administrative detention). It contrasts with 扣 (kòu), which is more general and can also mean 'to deduct'; 押 (yā), which often implies holding as security or escorting; and the compounds 扣押/扣留 (kòu yā / kòu liú), which are used for both persons and property (impound/confiscate). Use 拘留 specifically for the legal detention of a person.