security system
nounUK /sɪˈkjʊərəti ˈsɪstəm/
US /sɪˈkjʊrəti ˈsɪstəm/
A security system is a set of machines that keeps a place safe and warns people if there is danger.
Our house has a security system that beeps if a window opens.
OTHER MEANINGS
2. A group of computer programs and rules that protect a computer from harm.
The school updated its computer security system to stop viruses.
3. The way a country or group works to keep itself safe from attacks.
The country spent money on a new national security system.
4. A set of steps people follow to keep something safe.
The airport has a strict security system for checking bags.