An apparatus (plural apparatus, apparatuses) may be one of the following:

1. A machine , as in a fire engine or fire truck.

2. Reference tools added to a book, apart from the text, such as variant readings or translations, textual notes, a concordance, a bibliography, or an index, designed for the use of scholars studying the book.
3. One or more pieces of equipment on or with which gymnastics is performed.

-see also:
"Apparatus" is in the NAICS Code "334210"
(Telephone Apparatus ManufacturingToll switching equipment, telephone, manufacturing)