Origin of the word
Lock is derived from Old English ‘loc’ referring to a means for fastening, and down from Middle English ‘doun’. Lockdown has been used since the late 19th century, and is an example of a noun formed from the constituent parts of a phrasal verb. Another example is shutdown.
Lockdown is a noun that refers to a security measure resulting in people being prevented from leaving or entering a building in the event of an emergency. This method of confinement is used after a disturbance to minimize the possibility of damage or harm to individuals located around the incident.
Cromer, a popular seaside resort in the east of England, was apparently put on lockdown on Saturday during the closing weekend of the Cromer Carnival due to an outbreak of what police described as ‘anti-social behaviour and low-level disorder’. A series of incidents including thefts from local shops and disorderly behaviour in pubs and restaurants prompted local businesses to close their doors to the public, although no arrests were made.
An occasion or time when access to a place is restricted because of some danger.
View the full definition in the Macmillan Dictionary.