1vac·u·um 
/ˈvæˌkju:m/ noun
plural vac·u·ums /ˈvæˌkju:m/ noun [count] 1 : an empty space in which there is no air or other gas
▪ the vacuum of outer space : a space from which all or most of the air has been removed ▪ A pump was used to create a vacuum inside the bottle. ▪ a vacuum chamber 2 : vacuum cleaner 3 : a situation created when an important person or thing has gone and has not been replaced — usually singular ▪ Her death has caused/created/left a vacuum [=void] in our lives. ▪ A new leader is needed to fill the vacuum left by his retirement.
▪ the vacuum of outer space : a space from which all or most of the air has been removed ▪ A pump was used to create a vacuum inside the bottle. ▪ a vacuum chamber
in a vacuum
: separated from outside events or influences
▪ The group was operating in a vacuum, cut off from the rest of the world. ▪ The city's riots did not happen in a vacuum. [=they were affected or caused by other events or influences]
▪ The group was operating in a vacuum, cut off from the rest of the world. ▪ The city's riots did not happen in a vacuum. [=they were affected or caused by other events or influences]
