What does apparatus mean?
The definition of apparatus
Ap”pa*ratus, n.; pl. Apparatus, also rarely Apparatuses.
Etym: [L., from apparare, apparatum, to prepare; ad + prepare to make ready.]

1 Things provided as means to some end.
2 Hence: A full collection or set of implements, or utensils, for a given duty, experimental or operative; any complex instrument or appliance, mechanical or chemical, for a specific action or operation; machinery; mechanism.
3 (Physiol.)
A collection of organs all of which unite in a common function; as, the respiratory apparatus.