Definition of apparatus noun from the Oxford Advanced Learner's Dictionary
apparatus
noun
ˌæpəˈreɪtəs ˌæpəˈrætəs
pluralapparatuses
1[uncountable]the tools or other pieces of equipment that are needed for a particular activity or taska piece of laboratory apparatusFirefighters needed breathing apparatus to enter the burning house.2[countable, usually singular]the structure of a system or an organization, particularly that of a political party or a governmentthe power of the state apparatus3[countable, usually singular] (technical) a system of organs in the bodythe sensory apparatus
Usage note: equipmentmaterialgearkitapparatusThese are all words for the things that you need for a particular purpose or activity.equipment the things that are needed for a particular purpose or activity: camping equipment◇a piece of equipmentmaterial things that are needed for a particular activity: household cleaning materials◇teaching materialequipment or material?Equipment is usually solid things, especially large ones. Materials may be liquids, powders or books, CDs, etc. containing information, as well as small solid items.gear the equipment or clothes needed for a particular activity: Skiing gear can be expensive.kit a set of tools or equipment that you use for a particular purpose: a first-aid kit◇a tool kitapparatus the tools or other pieces of equipment that are needed for a particular activity or task: breathing apparatus for firefighters◇laboratory apparatusApparatus is used especially for scientific, medical or technical purposes.electrical/electronic equipment/gear/apparatussports equipment/gear/kitcamping equipment/geara piece of equipment/apparatus
ˌæpəˈreɪtəs 
ˌæpəˈrætəs 
Usage note: equipmentmaterial gear kit apparatusThese are all words for the things that you need for a particular purpose or activity.equipment the things that are needed for a particular purpose or activity: camping equipment ◇ a piece of equipmentmaterial things that are needed for a particular activity: household cleaning materials ◇ teaching materialequipment or material?Equipment is usually solid things, especially large ones. Materials may be liquids, powders or books, CDs, etc. containing information, as well as small solid items.gear the equipment or clothes needed for a particular activity: Skiing gear can be expensive.kit a set of tools or equipment that you use for a particular purpose: a first-aid kit ◇ a tool kitapparatus the tools or other pieces of equipment that are needed for a particular activity or task: breathing apparatus for firefighters ◇ laboratory apparatus Apparatus is used especially for scientific, medical or technical purposes.electrical/electronic equipment/gear/apparatussports equipment/gear/kitcamping equipment/geara piece of equipment/apparatus