apparatus

[ ap-uh-rat-uhs, -rey-tuhs ]

noun

, plural ap·pa·rat·us, ap·pa·rat·us·es.

1. a group or combination of instruments, machinery, tools, materials, etc., having a particular function or intended for a specific use:

   Our town has excellent fire-fighting apparatus.

2. any complex instrument or mechanism for a particular purpose.

   Synonyms: contrivance, contraption, device, appliance, machine

3. any system or systematic organization of activities, functions, processes, etc., directed toward a specific goal:

   the apparatus of government; espionage apparatus.

4. Physiology. a group of structurally different organs working together in the performance of a particular function:

   the digestive apparatus.

apparatus

/ ˌæpəˈreɪtəs; ˈæpəˌreɪtəs; -ˈrɑːtəs /

noun

1. a collection of instruments, machines, tools, parts, or other equipment used for a particular purpose
2. a machine having a specific function

   breathing apparatus

3. the means by which something operates; organization

   the apparatus of government

4. anatomy any group of organs having a specific function

Word History and Origins

Origin of apparatus¹

1620–30; < Latin apparātus equipment, originally the act of equipping, preparation, equivalent to apparā ( re ) to prepare ( ap- ap- ¹ + parāre; prepare ) + -tus suffix of v. action

Word History and Origins

Origin of apparatus¹

C17: from Latin, from apparāre to make ready

Example Sentences

Some national security experts say the move is in line with Trump’s skepticism toward the national security apparatus.

From Salon

But given the ephemeral nature of China’s censorship apparatus, those tags can quickly evolve.

From Los Angeles Times

"I prided myself on my health and fitness," says Nik, who now uses a motorised wheelchair and breathing apparatus.

From BBC

Crews wore breathing apparatus to enter the property and extinguished the blaze by 05:55 GMT.

From BBC

Firefighters wearing breathing apparatus "entered the property but very sadly, the bodies of two people were found inside," the fire service said.

From BBC

Related Words

• appliance
• device
• gear
• gizmo
• machine
• machinery
• means
• mechanism

What Is The Plural Of Apparatus?

Plural word for apparatus

The plural form of apparatus can be either apparatus or apparatuses. The appropriate plural form depends on whether the term is considered to be a mass (uncountable) noun (like air or rice) or a count noun (like apple or car). 

When used as a mass noun, the correct plural form is apparatus, as in The lab apparatus must be removed before the lab can be painted. 

When used as a count noun, the correct plural form is apparatuses, as in The ship is equipped with apparatuses for security, cargo loading, and more. The plurals of several other singular words that end in -s are also formed the same way, such as pass/passes, lotus/lotuses, and dress/dresses. 

In some nouns that end in -us that are derived from Latin, the irregular plural ending -i may be used instead, as in fungus/fungi or cactus/cacti. These nouns are considered irregular nouns.

However, this ending is not valid for apparatus. Apparati would be an invalid plural for apparatus.