apparatus: Meaning and Definition of

ap•pa•rat•us

1. a group or combination of instruments, machinery, tools, materials, etc., having a particular function or intended for a specific use: Our town has excellent fire-fighting apparatus.
2. any complex instrument or mechanism for a particular purpose.
3. any system or systematic organization of activities, functions, processes, etc., directed toward a specific goal: the apparatus of government; espionage apparatus.
4. a group of structurally different organs working together in the performance of a particular function: the digestive apparatus.