Security information and event management (SIEM) software products and services combine security information management (SIM) and security event management (SEM). They provide real-time analysis of security alerts generated by applications and network hardware.
Vendors sell SIEM as software, as appliances or as managed services; these products are also used to log security data and generate reports for compliance purposes.
See also:
SIM - Security Information Management
SEM - Security Event Management
References:
https://en.wikipedia.org/wiki/Security_information_and_event_management