lockdownPronunciation: /ˈlɒkdaʊn/Definition of lockdown noun North American the confining of prisoners to their cells, typically in order to regain control during a riot: the lockdown has been in effect since October 1983 a state of isolation or restricted access instituted as a security measure:the university is on lockdown and nobody has been able to leavelockdown in other Oxford dictionaries Definition of lockdown in the US English dictionary
