apparatus

The definition of an apparatus is a device or group of objects used for a specific purpose.

(noun)

Scuba gear is an example of a breathing apparatus.

See apparatus in Webster's New World College Dictionary

the instruments, materials, tools, etc. needed for a specific use
any complex device or machine for a specific use
Physiol. a set of organs having a specific function: the digestive apparatus
the means or system by which something is kept in action or a desired result is obtained; organization: the apparatus of government
the notes, indexes, glossaries, etc. of a scholarly edition of a text
in full apparatus criticus

Origin: L, a making ready, preparation < apparare < ad-, to + parare, prepare

See apparatus in American Heritage Dictionary 4

noun pl. apparatus apparatus or ap·pa·rat·us·es

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.
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.
Physiology A group or system of organs that collectively perform a specific function or process: the respiratory apparatus; the digestive apparatus.
The critical and source material that accompanies an edition of a text.