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:
They’re up against the entire apparatus that allowed Skydance to become what it is now.
From Slate ● Oct. 16, 2026
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
Leagues are run in service of franchise owners; the whole apparatus is designed to protect the brand aka the valuations.
From The Wall Street Journal ● Sep. 3, 2026
The Thai government is "using the security apparatus to solve the problem", the rights advocate Kannavee said.
From Barron's ● Aug. 26, 2026
There was no evidence that hydrogen ions had charged around Edlefsen’s “rather sketchy” apparatus at all, much less at any appreciable fraction of 1 million electron volts.
From "Big Science" by Michael Hiltzik
"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
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
Because information about these facilities is closely guarded — including their location and the details of their security apparatuses — the thieves who target them often have inside information, according to news reports.
From Los Angeles Times ● May 9, 2024
Gymnasts set up their apparatuses, but with the ship swaying, they kept getting bucked off.
From "Unbroken" by Laura Hillenbrand
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Get a wordDefinitions 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.
