Just Enough Operating System (JeOS)
Definition - What does Just Enough Operating System (JeOS) mean?
Techopedia explains Just Enough Operating System (JeOS)
JeOS designers have to consider a given OS' kernel or core, as well as tools and utilities required to create a custom OS that enables faster operations and less required installation memory. The use of JeOS designs often corresponds to a virtual appliance method, where a virtual machine (VM) image runs on a given platform.
There also is a tendency for open source operating systems to lead the pack, in terms of JeOS development, even though this model is being adopted by other major licensed operating systems.