SIEM
In plain terms
A system aggregating and analyzing security data for threats.
Going deeper
Security Information and Event Management collects logs and events across an organization to detect, alert on, and investigate security incidents. It centralizes monitoring.
Under the hood
Correlates events for detection and compliance; modern SIEMs add analytics and automated response (SOAR).
Examples
Splunk, log correlation, threat detection, SOC operations, compliance.
Think of it like...
Like a central security operations center watching feeds from every camera at once.