I. noun 1. [ mass noun] — the technical equipment or machinery needed for a particular activity or purpose • firemen wearing breathing apparatus.
2. the complex structure of a particular organization or system • the apparatus of government.
3. (also critical apparatus) — a collection of notes, variant readings, and other matter accompanying a printed text. • one thing about the book’s apparatus does irritate: the absence of an index of titles.
– origin early 17th cent.: Latin, from apparare ‘make ready for’, from ad- ‘towards’ + parare ‘make ready’.