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a. A protocol followed in an emergency that involves confining people in a secure place, such as the confinement of prison inmates in cells after a disturbance, or the locking of students and teachers in classrooms after a violent attack.
b. A situation in which this protocol is undertaken.
2. A facility, such as a prison, where people considered to be dangerous are locked inside living quarters or otherwise confined.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(Law) US a security measure in which those inside a building such as a prison, school, or hospital are required to remain confined in it for a time: many schools remained under lockdown yesterday.
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014



the confining of prisoners to their cells, as following a riot or other disturbance.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.lockdown - the act of confining prisoners to their cells (usually to regain control during a riot)
internment, imprisonment - the act of confining someone in a prison (or as if in a prison)
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.


lock-down [ˈlɒkdaʊn] n
to be in lockdown, to be under lockdown [place] → faire l'objet de mesures de confinement
to be on lockdown [prisoner] → être confiné(e) en cellule, être confiné(e) dans sa cellule
Collins English/French Electronic Resource. © HarperCollins Publishers 2005
References in periodicals archive ?
An unprecedented security lockdown and near total communication blockade has continued since Sunday night in occupied Kashmir, a day before the Hindu nationalist-led government in New Delhi scrapped the disputed Himalayan region's autonomous status.
The date and venue of the 'lockdown' could not be agreed upon at the huddle, which was not attended by Pakistan Muslim League-Nawaz (PML-N) President Shahbaz Sharif and Pakistan Peoples Party (PPP) Chairman Bilawal Bhutto Zardari.
ISLAMABAD -- The opposition parties have decided to 'lockdown' the federal capital in protest against the Pakistan Tehreek-e-Insaf (PTI) government's policies, especially its ongoing accountability drive largely targeting the opposition leaders.
MUZAFFARABAD -- Scores of people, including women and children, most of them from the divided Kashmiri families, staged a rally here on Sunday to condemn India for subjecting occupied Kashmir to lockdown, curfew and communication blockade for the 'success' of its attempts to merge the disputed Himalayan region.
At least three businesses in the area are on lockdown. Three Walmart employees took refuge at a Landry's Seafood house, restaurant manager Oscar Collazo told CNN.
Garda chase puts Dublin in lockdown THREE men were arrested after a high-speed car chase put Dublin on lockdown last night.
A SMASHED window forced a school into "lockdown" yesterday.
Summary: Washington [USA], Jun 20 (ANI): The US Secret Services have put the White House area on lockdown after an individual "dropped a backpack" and "attempted to jump a bike rack" near the estate on Wednesday.
A BIRMINGHAM school was placed in lockdown after police were called to deal with an intruder.
Residents from the towns of Patikul, Indanan and Maimbung in Sulu province complained of a six-hour lockdown in Jolo on Sunday that prevented them from getting inside the town and nearly depriving them of food for their evening's breaking of the fast (iftar) for Ramadan.
A DuPage County jail inmate already being held on $75,000 bail for threatening a Glenbard East High School student, picked up a new charge after he caused a lockdown Tuesday night, authorities said.