Security and privacy
ESU
Abbreviation for Extended Security Updates
In short and in plain language
ESU is a program that gives more updates to keep you safe.
It is for the system on a computer when its normal support ends.
So an old computer still gets fixes for safety for a while.
Definition
ESU is a program of extended security updates for an operating system after regular support has ended. It keeps an older computer supplied with security fixes for a while longer.