subsystem
set of elements, which is a system itself, and a component of a larger system
organ system
group of organs that work together to perform one or more functions; collection of organs joined in structural unit to serve a common function
power management
a feature of some electrical appliances
structural system
load-resisting sub-system of a structure
microsystem
miniaturized device performing electrical and non-electronic functions
base station subsystem
the section of a cellular telephone network responsible for handling traffic and signaling