a country, building or person against attack, danger, etc. 2. a place at an airport where you go after your passport has been checked so that officials can find out if you are carrying illegal drugs or weapons 3. the department of a large company or organization that deals with the protection of its buildings, equipment and staff 4. protection against something bad that might happen in the future ref: https://www.oxfordlearnersdictionaries.com/definition/english/security?q=security