apparatus
Americannoun
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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.
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any complex instrument or mechanism for a particular purpose.
- Synonyms:
- contrivance, contraption, device, appliance, machine
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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
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a collection of instruments, machines, tools, parts, or other equipment used for a particular purpose
-
a machine having a specific function
breathing apparatus
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the means by which something operates; organization
the apparatus of government
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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:
Today the veterans there are led by Prigozhin’s son, Pavel Prigozhin, who has leveraged the group’s deep knowledge of the country’s security and intelligence apparatus.
From The Wall Street Journal ● Jul. 12, 2026
His apparatus ultimately penetrated U.S. intelligence and diplomatic circles through some of Cuba’s most successful espionage operations.
From The Wall Street Journal ● Jun. 24, 2026
Picture this: a team of camera-clad cleaners and a private chef to boot, all wired with high-tech recording apparatus show up at your home.
From BBC ● Jun. 20, 2026
He embedded a whole apparatus of passages and outbuildings into the descending terrain to the east, concealing them so effectively from view that from the west Monticello has the character of an isolated hilltop temple.
From The Wall Street Journal ● Jun. 19, 2026
The trend line pointed to a future of intense and expensive competition among academic institutions to be first with high-priced research apparatus.
From "Big Science" by Michael Hiltzik
Iran, Russia and North Korea have all built elaborate apparatuses to skirt financial blockades.
From The Wall Street Journal ● Jun. 21, 2026
“We used multiple aerial apparatuses, fire engines and rescues to help combat this incident,” Byrd said.
From Los Angeles Times ● Nov. 6, 2025
Chief Crowley has also attacked city leadership for cutting her department's budget and eliminating mechanic positions, which she said had resulted in more than 100 fire apparatuses being out of service.
From BBC ● Jan. 11, 2025
The women of Team USA's gymnastics team capped off an incredibly strong showing at the Paris Olympics on Monay, set to return home with an assortment of medals from various apparatuses.
From Salon ● Aug. 5, 2024
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.
