apparatus
Americannoun
-
apparatus,
plural
-
apparatuses
plural
-
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.
-
any complex instrument or mechanism for a particular purpose.
- Synonyms:
- contrivance, contraption, device, appliance, machine
-
any system or systematic organization of activities, functions, processes, etc., directed toward a specific goal.
the apparatus of government; espionage apparatus.
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Physiology. a group of structurally different organs working together in the performance of a particular function.
the digestive apparatus.
noun
-
a collection of instruments, machines, tools, parts, or other equipment used for a particular purpose
-
a machine having a specific function
breathing apparatus
-
the means by which something operates; organization
the apparatus of government
-
anatomy any group of organs having a specific function
Usage
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.
Other Word Forms
Noun Inflected Forms
Etymology
Origin of apparatus
1620–30; < Latin apparātus equipment, originally the act of equipping, preparation, equivalent to apparā ( re ) to prepare ( ap- ap- 1 + parāre; see prepare) + -tus suffix of v. action
Explanation
Your apparatus is the collective equipment you use for specific purposes. For example, the apparatus used for scuba diving includes goggles, flippers, and a breathing tank, while a surgeon’s apparatus includes various scalpels and clamps. Different activities, different apparatuses. The noun apparatus evolved from the Latin apparātus, meaning "equipment or preparation." It might refer to one item, (a breathing apparatus) or a group of items (sports apparatus). Here’s a spelling tip: often, when a word ends in -us, the plural ending changes to i — “alumnus/alumni,” “focus/foci.” However, apparatus is part of the group that doesn't change — words like “virus/viruses” or “census/censuses.” This means the plural is either apparatus or apparatuses, though the latter is more common.
Vocabulary lists containing apparatus
Orbiting Jupiter
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Among the Hidden
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The Time Machine
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
The researchers connected their thorium excitation apparatus to a conventional optical atomic clock, demonstrating that the nuclei could serve as a highly precise timekeeping reference.
From Science Daily ● Oct. 11, 2026
He’s used the apparatus for about 70% of his training mileage for Sunday’s marathon.
From The Wall Street Journal ● Oct. 10, 2026
“That was the most difficult thing to learn because, as a dancer, you have such a relationship to the floor and you have to dance with an apparatus that doesn’t quite move with you.”
From Los Angeles Times ● Sep. 14, 2026
Ochieng said the mutiny "demonstrates deep divisions and grievances within the security apparatus", in a country whose soldiers are "constantly in the line of fire, fighting militants".
From Barron's ● Sep. 1, 2026
If this really is a police apparatus, here; if it’s what it asserts itself to be.
From "Do Androids Dream of Electric Sheep?" by Philip K. Dick
"A total of 60 fire apparatuses arrived, just short, just shy of 200 men and women from Miami-Dade Fire Rescue, to begin the actual search and rescue and firefighting," Jadallah said.
From Barron's ● Sep. 6, 2026
For example, Crypto.com Arena’s footprint will be changed to accommodate artistic gymnastics, with up to six apparatuses on the floor along with areas for judges, broadcast positions and media.
From Los Angeles Times ● Aug. 21, 2026
Will people start wearing N95 masks indoors, or have breathing apparatuses hooked up to their chests like fighter pilots?
From Salon ● Jul. 19, 2026
Iran, Russia and North Korea have all built elaborate apparatuses to skirt financial blockades.
From The Wall Street Journal ● Jun. 21, 2026
Gymnasts set up their apparatuses, but with the ship swaying, they kept getting bucked off.
From "Unbroken" by Laura Hillenbrand
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
