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  • core
    core
    noun
    the central part of a fleshy fruit, containing the seeds.
  • Core
    Core
    noun
  • CORE
    CORE
    noun
    Congress of Racial Equality.
  • -core
    -core
    a combining form extracted from hard-core, used to form words that name a rebellious or nonmainstream lifestyle, social movement, type of music, etc..
Synonyms

core

1 American  
[kawr] / kɔr /

noun

  1. the central part of a fleshy fruit, containing the seeds.

  2. the central, innermost, or most essential part of anything.

    Synonyms:
    center, nub, kernel, gist, heart, essence
  3. Also called magnetic coreElectricity. 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.

  4. (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.

  5. the inside wood of a tree.

  6. Anthropology. a lump of stone, as flint, from which prehistoric humans struck flakes in order to make tools.

  7. Carpentry.

    1. a thickness of wood forming a base for a veneer.

    2. a wooden construction, as in a door, forming a backing for veneers.

  8. Engineering. kern.

  9. Metallurgy.

    1. a thickness of base metal beneath a cladding.

    2. the softer interior of a piece of casehardened metal.

    3. 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.

  10. 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.

  11. Also called reactor corePhysics. the region in a reactor that contains its fissionable material.

  12. Computers.

    1. 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.

    2. 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.

  13. Ropemaking. heart.

  14. Phonetics. the final segment of a syllable beginning with the vowel and including any following consonants; the nucleus plus the coda.

  15. 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)

cores, present (3rd person singular) cored, past participle, past coring present participle
  1. to remove the core of (fruit).

  2. to cut from the central part.

  3. to remove (a cylindrical sample) from the interior, as of the earth or a tree trunk.

    to core the ocean bottom.

  4. to form a cavity in (a molded object) by placing a core, as of sand, in the mold before pouring.

adjective

  1. of central importance; basic; fundamental.

    the core values of our organization.

  2. noting or relating to the muscles of the torso.

    core exercises for back pain.

core 2 American  
[kawr, kohr] / kɔr, koʊr /

noun

Chiefly Scot.
  1. a small company or group of people, especially a gang of miners or a small corps of workers.


Core 3 American  
[kawr-ee, kohr-ee] / ˈkɔr i, ˈkoʊr i /

noun

  1. Korah.

  2. Classical Mythology. Kore.


CORE 4 American  
[kawr, kohr] / kɔr, koʊr /
Or C.O.R.E.

noun

  1. Congress of Racial Equality.


-core 5 American  
  1. a combining form extracted from hard-core, used to form words that name a rebellious or nonmainstream lifestyle, social movement, type of music, etc..

  2. 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..


-core 1 British  

combining form

  1. indicating a type of popular music

    dancecore

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

combining form

  1. indicating the number of processing units working in parallel in a computer

    dual-core

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
CORE 2 British  
/ kɔː /

acronym

  1. Congress of Racial Equality

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

core 3 British  
/ kɔː /

noun

  1. the central part of certain fleshy fruits, such as the apple or pear, consisting of the seeds and supporting parts

    1. the central, innermost, or most essential part of something

      the core of the argument

    2. ( as modifier )

      the core meaning

  2. 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

  3. 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

  4. a cylindrical sample of rock, soil, etc, obtained by the use of a hollow drill

  5. 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

  6. physics the region of a nuclear reactor in which the reaction takes place

  7. a layer of wood serving as a backing for a veneer

  8. computing

    1. one of several processing units working in parallel in a computer

    2. a ferrite ring formerly used in a computer memory to store one bit of information

    3. short for core store

    4. ( as modifier )

      core memory

  9. archaeol a lump of stone or flint from which flakes or blades have been removed

  10. physics the nucleus together with all complete electron shells of an atom

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

verb

  1. (tr) to remove the core from (fruit)

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
core Scientific  
/ kôr /
  1. 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).

  2. 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.

  3. The central part of a nuclear reactor where atomic fission occurs. The core contains the fuel, the coolant, and the moderator.

  4. 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.

  5. 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.

  6. See more at core tool


core Cultural  
  1. In geology, the central region of the Earth; it extends fourteen hundred to eighteen hundred miles from the Earth's center.


core Idioms  

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

Past

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.

Keep Reading on Vocabulary.com

Vocabulary lists containing core

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:

Measures of core inflation, which exclude volatile food and energy prices, have been stubborn too, suggesting that some of the inflation rebound springs from deeper economic trends.

From The Wall Street Journal Jul. 14, 2026

I’ve always thought it’s very important, back to the “Tim & Eric” days — it built from a core audience that we were pretty active within and responsive to.

From Los Angeles Times Jul. 14, 2026

Their earlier work, published in Physical Review D, examined how mass segregation influences the wide range of dark matter core densities observed in dwarf galaxies.

From Science Daily Jul. 14, 2026

None of these reforms would displace Slaughter’s core holding.

From Slate Jul. 13, 2026

Both sides could plausibly claim a core strand of the revolutionary legacy as their own.

From "Founding Brothers: The Revolutionary Generation" by Joseph J. Ellis

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 PCE strips out food and energy, but it can still be skewed by a handful of unusually large price moves.

From MarketWatch Jun. 29, 2026

Core PCE inflation rose 0.3% on the month in May, and increased 3.4% compared with a year ago, well above the Fed’s 2% target.

From Barron's Jun. 25, 2026

Core inflation excluding volatile food and energy costs ticked up to 1.6% from a year earlier.

From The Wall Street Journal Jun. 22, 2026

In defending these new standards, David Coleman, president of the College Board and one of the architects of the Common Core, seemed to equate reading and writing that is not purely fact-based with self-indulgence.

From "Drama High" by Michael Sokolove

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

Black church congregations folded bills hidden inside envelopes and sent the money to the Southern Christian Leadership Conference, to the Student Non-Violent Coordinating Committee, to the NAACP, to CORE.

From Washington Post Apr. 25, 2023

Many of them already knew of Carey from his role as field secretary of the nation’s oldest and preeminent direct-action civil rights group: the Congress of Racial Equality, or CORE.

From "The Best of Enemies" by Osha Gray Davidson

These dense stellar remnants are the leftover cores of Sun like stars that have exhausted their fuel and collapsed to only about 1% of their original size.

From Science Daily Jul. 10, 2026

So they turn to cut-through notches, carved light wells, and strategic wall-offs of interior cores that create space for new residential floors.

From The Wall Street Journal Jul. 7, 2026

Current models suggest rocky planets form near stars because intense radiation strips away gas surrounding developing planetary cores.

From Science Daily May 21, 2026

For example, A18 Pro chips with 6 GPU cores originally appeared in 2024 in the iPhone 16 Pro models.

From The Wall Street Journal May 18, 2026

Lying low made sense because we were up the creek with models based on sugar-phosphate cores.

From "Double Helix" by James D. Watson

Engineers hope spherical tokamaks–shaped like a cored apple rather than a doughnut—can be built smaller and more cheaply than conventional tokamaks.

From Science Magazine Sep. 7, 2023

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

Crusts.—Cut stale bread in circles, lay half of a peeled and cored apple on each piece.

From The Myrtle Reed Cook Book by Reed, Myrtle

Their work included sediment coring, laboratory testing, climate reconstructions, and studies of past plant and animal activity.

From Science Daily Jun. 11, 2026

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

She joined Neff in pushing for the Thwaites collaboration to include ice coring, but a combination of competing priorities, perpetually bad weather, and difficult logistics stood in the way.

From Science Magazine Apr. 18, 2024

Toasting bread and cheese, coring apples, placing chestnuts in the fire to roast.

From "Catching Fire" by Suzanne Collins

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