apparatus

(ăpˌə-rătˈəs, -rāˈtəs)

1. a. An appliance or device for a particular purpose: an x-ray apparatus.
   b. An integrated group of materials or devices used for a particular purpose: dental apparatus. See Synonyms at equipment.
2. a. The totality of means by which a designated function is performed or a specific task executed, as in a system of government.
   b. A political organization or an underground political movement. Also called apparat.
3. Physiology A group or system of organs that collectively perform a specific function or process: the respiratory apparatus; the digestive apparatus.
4. The critical and source material that accompanies an edition of a text.