The confinement of people in their own rooms (e.g., in a school) or cells (in a prison), or to their own homes or areas (e.g., in the case of a city- or nation-wide issue) as a security measure after or amid a disturbance or as a non-pharmaceutical intervention in a pandemic.

plural of lockdown

(education) A software package, essentially a restricted web browser, that prevents users from navigating away from a particular online task, commonly used when holding tests, quizzes, etc.

plural of lockdown browser