1. the confining of prisoners to their cells, typically to regain control during a disturbance
Usage: prison context
2. an emergency protocol that prevents people from leaving or entering a building or area
Usage: security context
3. a state of restricted movement and activity imposed by authorities, especially during a public health emergency
Usage: public health context

Examples

• The prison was placed under lockdown after the riot.
• The school initiated a lockdown when an intruder was spotted on campus.
• Students practiced lockdown procedures during the safety drill.
• The government imposed a nationwide lockdown to slow the spread of the virus.
• Many businesses closed during the lockdown.
• The lockdown lasted for several weeks before restrictions were lifted.
• Emergency services responded quickly to the hospital lockdown.