Pronunciation: (ap"u-rat'us, -rā'tus),[key] —n., —pl.-tus, -tus•es. 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. Physiol.a group of structurally different organs working together in the performance of a particular function: the digestive apparatus.