IPA: /ˈkɜːrfjuː/
KK: /ˈkɜrˌfju/
A rule that requires people to be at home or off the streets by a certain time, often set by authorities.
The city imposed a curfew to keep everyone safe during the unrest.
Curfew comes from the Old French 'curfeu', which is derived from 'cueillir' (meaning to cover) and 'feu' (meaning fire). The term originally referred to the time when the fire was to be covered or extinguished, marking the end of the day.
Think of the idea of 'covering' a 'fire' at a certain time — that's how curfew relates to the time when activities must cease.