"subsystem" - key terms from Wikipedia

area weapon subsystem
armament subsystem
audio subsystem
base station subsystem
control subsystem
defensive armament subsystem
disk subsystem
environment subsystem
headgear subsystem
imaging science subsystem
integral subsystem
ip multimedia subsystem
local security authority subsystem	service
memory subsystem
messaging subsystem
power subsystem
print subsystem
propulsion subsystem
protection subsystem
subsystem
subsystem	helps
transmission subsystem