core
1 Americannoun
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the central part of a fleshy fruit, containing the seeds.
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the central, innermost, or most essential part of anything.
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Also called magnetic core. Electricity. the piece of iron, bundle of iron wires, or other ferrous material forming the central or inner portion in an electromagnet, induction coil, transformer, or the like.
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(in mining, geology, etc.) a cylindrical sample of earth, mineral, or rock extracted from the ground by means of a corer so that the strata are undisturbed in the sample.
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the inside wood of a tree.
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Anthropology. a lump of stone, as flint, from which prehistoric humans struck flakes in order to make tools.
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Carpentry.
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a thickness of wood forming a base for a veneer.
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a wooden construction, as in a door, forming a backing for veneers.
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Engineering. kern.
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Metallurgy.
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a thickness of base metal beneath a cladding.
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the softer interior of a piece of casehardened metal.
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a specially formed refractory object inserted into a mold to produce cavities or depressions in the casting that cannot be readily formed on the pattern.
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Geology. the central portion of the earth, having a radius of about 2,100 miles (3,379 km) and believed to be composed mainly of iron and nickel in a molten state.
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Also called reactor core. Physics. the region in a reactor that contains its fissionable material.
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Computers.
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Also called magnetic core. a small ring or loop of ferromagnetic material with two states of polarization that can be changed by changing the direction of the current applied in wires wound around the ring, used to store one bit of information or to perform switching or logical functions.
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Also called main memory. Also called RAM. a term used to refer to main memory, though no longer made from from coils of ferromagnetic material.
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Ropemaking. heart.
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Phonetics. the final segment of a syllable beginning with the vowel and including any following consonants; the nucleus plus the coda.
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the muscles of the torso, which provide support for the spine and pelvis.
Building a strong core can help with posture and flexibility and can prevent back injury.
verb (used with object)
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to remove the core of (fruit).
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to cut from the central part.
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to remove (a cylindrical sample) from the interior, as of the earth or a tree trunk.
to core the ocean bottom.
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to form a cavity in (a molded object) by placing a core, as of sand, in the mold before pouring.
adjective
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of central importance; basic; fundamental.
the core values of our organization.
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noting or relating to the muscles of the torso.
core exercises for back pain.
noun
noun
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a combining form extracted from hard-core, used to form words that name a rebellious or nonmainstream lifestyle, social movement, type of music, etc..
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the compounding form of core, used to form words describing an aesthetic or imagery that evokes nostalgia for vintage styles, traditional skills, past trends, etc..
acronym
noun
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the central part of certain fleshy fruits, such as the apple or pear, consisting of the seeds and supporting parts
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the central, innermost, or most essential part of something
the core of the argument
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( as modifier )
the core meaning
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a piece of magnetic material, such as soft iron, placed inside the windings of an electromagnet or transformer to intensify and direct the magnetic field
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geology the central part of the earth, beneath the mantle, consisting mainly of iron and nickel, which has an inner solid part surrounded by an outer liquid part
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a cylindrical sample of rock, soil, etc, obtained by the use of a hollow drill
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shaped body of material (in metal casting usually of sand) supported inside a mould to form a cavity of predetermined shape in the finished casting
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physics the region of a nuclear reactor in which the reaction takes place
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a layer of wood serving as a backing for a veneer
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computing
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one of several processing units working in parallel in a computer
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a ferrite ring formerly used in a computer memory to store one bit of information
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short for core store
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( as modifier )
core memory
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archaeol a lump of stone or flint from which flakes or blades have been removed
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physics the nucleus together with all complete electron shells of an atom
verb
combining form
combining form
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The central or innermost portion of the Earth, lying below the mantle and probably consisting of iron and nickel. It is divided into a liquid outer core, which begins at a depth of 2,898 km (1,800 mi), and a solid inner core, which begins at a depth of 4,983 km (3,090 mi).
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A piece of magnetizable material, such as a rod of soft iron, that is placed inside an electrical coil or transformer to intensify and provide a path for the magnetic field produced by the current running through the wire windings.
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The central part of a nuclear reactor where atomic fission occurs. The core contains the fuel, the coolant, and the moderator.
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A long, cylindrical sample of soil, rock, or ice collected with a drill to study the strata of material that are not visible from the surface.
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A stone from which one or more flakes have been removed, serving as a tool in itself or as a source of flakes from which other tools could be fashioned. Stones used as cores include flint, chert, and obsidian.
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See more at core tool
Usage
What does -core mean? The combining form -core is used like a suffix to denote "a rebellious, anti-mainstream lifestyle, social movement, type of music, etc."The form -core comes from the expression hardcore, "a form of punk rock or other nonmainstream popular music." Hardcore can denote not just a kind of a music but an entire lifestyle culture. From this, -core came to denote other music scenes, lifestyle cultures, or aesthetics.
Discover More
The core is made primarily of iron and nickel and has two parts — an inner solid core and an outer liquid core.
The mantle is the layer of the Earth that overlies the core.
Other Word Forms
Derived Forms
Inflected Forms
Participles
Conjugated Forms
Present
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coresimple
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coressimple
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have coredperfect
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has coredperfect
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am coringprogressive
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are coringprogressive
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is coringprogressive
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have been coringperfect progressive
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has been coringperfect progressive
Past
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coredsimple
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had coredperfect
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was coringprogressive
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were coringprogressive
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had been coringperfect progressive
Future
Etymology
Origin of core1
First recorded in 1350–1400; 1945–50 core 1 for def. 11; Middle English; origin uncertain; perhaps from Old French cors “body,” from Latin corpus
Origin of core2
First recorded in 1620–30; alteration of Middle English chor(e) “group, company; choir”; see chorus
Explanation
If you're looking for the most essential part or the very center of something, you're looking for its core. Like the inedible middle of an apple or your inner circle of core friends. In the late 14th century, the noun core came about from the Old French coeur, meaning “core of fruit” and more literally, “heart.” So the core of something is its very heart, whether you're talking about the seed-containing center of a fruit, the central meaning of a book, or the core courses you need to take in order to graduate.
Vocabulary lists containing core
The SAT: Multiple-Meaning Words, List 8
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The New SAT: Multiple-Meaning Words
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Physical Geography - Introductory
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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:
He, as usual, gets to the core of what is wrong in our country today.
From The Wall Street Journal ● Jul. 27, 2026
Such controversies highlight the delicate balance facing brands hoping to attract younger audiences without alienating their core, longstanding customer base.
From BBC ● Jul. 27, 2026
The power company’s core revenue does not depend on persuading residential regulators to approve higher bills every two years.
From MarketWatch ● Jul. 27, 2026
“Sponteneity and fun is cool, but if you don’t align with someone on basic core values that relationship is inevitably going to come to a halt,” she said.
From The Wall Street Journal ● Jul. 27, 2026
The idea of trying to get something for nothing offended him to the core, and he made this very clear.
From "The Long-Lost Home" by Maryrose Wood
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Core CPI was also 2.6% in the 12 months to June, which was unchanged from May.
From BBC ● Jul. 22, 2026
Core earnings per share, which excludes nonrecurring items, rose to $2.20 from $2.12 a year ago and topped the FactSet EPS consensus of $2.19.
From MarketWatch ● Jul. 9, 2026
Downtown has seen a few bright spots on the venue map, with newly-opened Pacific Electric in Chinatown and a revamped Bar Franca in the Historic Core.
From Los Angeles Times ● Jul. 8, 2026
Core inflation—which strips out more volatile energy and food prices—fell back to 2.4% in June from 2.6% in May.
From The Wall Street Journal ● Jul. 1, 2026
The Common Core Standards, however, are only written for English Language Arts and Mathematics, with no further intent to include other subject areas.
From "Music and the Child" by Natalie Sarrazin
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Earlier this month, L.A.-based aid organization Community Organized Relief Effort, or CORE, founded by Sean Penn and Ann Lee, broke ground on one of the hamlet’s newest local gathering spots: the Altadena Center for Community.
From Los Angeles Times ● Feb. 4, 2026
Building and training an LLM from scratch is too costly for all but the wealthiest organizations, says Petr Knoth, director of CORE, the world’s largest repository of open-access papers.
From Science Magazine ● Nov. 21, 2023
Ann Lee, co-founder of US-based crisis response group CORE, which is still operating in the capital, said that many international groups had left due to increasing intimidation and violence against staff.
From BBC ● Aug. 18, 2023
He would later join the Congress of Racial Equality, or CORE, along with his wife, brother and sister-in-law.
From Seattle Times ● Jun. 8, 2023
Although McKissick presided over the beginning of these changes, Joycelyn McKissick says her father never favored a blacks-only CORE.
From "The Best of Enemies" by Osha Gray Davidson
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IBM’s mainframe processors have huge amounts of on-chip memory, yet relatively few very fast computing cores.
From The Wall Street Journal ● Jul. 23, 2026
In this phase, the 18A-P process node is tested across chip cores ahead of general production.
From MarketWatch ● Jul. 22, 2026
The oldest and deepest pollen and spores in the cores remained lightly colored.
From Science Daily ● Jul. 22, 2026
The researchers identified the ancient drying event by studying sediment cores taken from some of K'gari's oldest lakes.
From Science Daily ● Jul. 21, 2026
Greenland ice cores show that the Toba blast was followed by at least six years of "volcanic winter" and goodness knows how many poor growing seasons after that.
From "A Short History of Nearly Everything" by Bill Bryson
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Lately there has been increasing interest in smaller devices with a more spherical shape, like a cored apple.
From Scientific American ● Jun. 5, 2023
The Astros cored a run off Murfee and four off Tommy Milone and another off Ryan Borucki.
From Seattle Times ● Jul. 29, 2022
Where bad apples threaten to ruin the barrel they are typically cored and turned to applesauce by hour’s end, unless it’s a two-part story or a seasonal arc.
From Los Angeles Times ● Oct. 6, 2021
Scientists extracted 471 metres of cored ice from Mount Huascarán.Credit:
From Nature ● Sep. 3, 2019
Three or four at a cent apiece should be pared and cored, and placed in a low baking-dish with two dessertspoonfuls of tapioca, and enough water to cover the whole.
From The Century Cook Book by Ronald, Mary
It’s comfortable in my hand, sharp and precise without feeling fussy, and it turns the quiet, repetitive work of cooking — chopping onions, coring fruit, slicing protein — into something smoother, even a little satisfying.
From Salon ● Apr. 21, 2026
Researchers used a special coring drill - a bit like a huge apple-corer - tethered to a research ship, to drill at depths of up to 500m.
From BBC ● Aug. 18, 2025
And the South Koreans were familiar with using helicopters for ice coring.
From Science Magazine ● Apr. 18, 2024
While balancing on the small raft, they'd screw metal rods together to lower a long slender coring tube over 50 feet to the lake bottom.
From Science Daily ● Oct. 17, 2023
Toasting bread and cheese, coring apples, placing chestnuts in the fire to roast.
From "Catching Fire" by Suzanne Collins
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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.