Core

/kɔː/ adj, name, noun, verb, slang

adj, name, noun, verb, slang ·Top 500 ·Elementary level

Meaning at a glance

  • Primary sense: In general usage, an essential part of a thing surrounded by other essential things.; The central part of a fruit, containing the kernels or seeds.
  • Grammar: core is listed as adj, name, noun, verb, slang.
  • Nearest alternatives: gist, center, crux, essence.
  • Useful contrasts: advanced society, ecological unit boundary, elective course.
  • Usage evidence: This is the core of the problem.

How to use "core"

  1. Start with the primary definition, then check the part of speech before placing the word in a sentence.
  2. Compare nearby synonyms to make sure "core" carries the exact meaning, tone, and strength you need.
  3. Use the example sentence as a context check. If your sentence uses the word differently, confirm that the grammar still fits.

Meaning check

  • Does the word fit the sentence's grammar?
  • Does it match the intended tone rather than only the dictionary definition?
  • Would a simpler synonym be clearer for the reader?
  • Is there enough surrounding context to prevent ambiguity?

Source and review context

This entry combines structured lexical data with WordToolSet review checks. Definitions, examples, synonyms, and usage notes may come from different source tables, so the page is designed to show evidence from more than one angle before you rely on "core" in a final draft.

If a word has several senses, prefer the sense that matches your sentence's grammar and surrounding context. A correct definition can still be the wrong choice when the sentence needs a different register, emphasis, or level of specificity.

Before you rely on this definition

Read the first definition as a starting point, then check the example, synonyms, and part of speech before treating "core" as the right word for your sentence.

If your draft is formal, technical, persuasive, or sensitive, compare "core" with a nearby alternative so the final choice matches both meaning and reader expectation.

Compare nearby meanings

  • Use synonyms when you need a softer, stronger, simpler, or more specific word.
  • Use antonyms to check the boundary of the meaning and avoid accidental contrast.
  • Use the example sentence to confirm the word behaves naturally in context.
  • Keep the original wording when a replacement adds complexity without improving precision.

Definition decision workflow

1. Identify the role

Check whether "core" is acting as adj, name, noun, verb, slang in your sentence. A definition is only useful when the grammar matches the way the word is being used.

2. Test the nearest option

Compare it with "gist" and other nearby choices to see whether the sentence needs a softer, stronger, or more familiar word.

3. Confirm with context

Use the example sentence below as an evidence check, then read your own sentence out loud to catch tone or rhythm problems.

Review note: Definition pages are checked for source coverage, sentence evidence, synonym support, and editorial insight before they are treated as approval-ready pages. If the evidence is too thin, the page remains available to users but is kept out of the approval-facing indexed inventory.

Final meaning check

Before publishing a sentence with "core", ask whether the word helps the reader understand the idea faster. A precise word should reduce confusion, not simply make the sentence look more polished.

When the definition, synonym evidence, and example context point in the same direction, the word is usually a safer choice. When they conflict, revise the sentence or choose a clearer alternative.

Definitions

Noun
  1. 1
    In general usage, an essential part of a thing surrounded by other essential things.; The central part of a fruit, containing the kernels or seeds. countable, uncountable

    "the core of an apple or quince"

  2. 2
    A body of individuals; an assemblage. obsolete

    "He was in a core of people."

  3. 3
    A miner's underground working time or shift.
  4. 4
    Alternative form of cor: a former Hebrew and Phoenician unit of volume. alt-of, alternative, historical
  5. 5
    A deposit paid by the purchaser of a rebuilt part, to be refunded on return of a used, rebuildable part, or the returned rebuildable part itself.
Show 33 more definitions
  1. 6
    An aesthetic ending in the suffix -core, such as cottagecore, normcore, etc. neologism

    "Some of the most popular "cores" at the moment—according to the Wiki's "trending pages" list—are cottage and goblin and trauma and angel. If the last one sounds appealing, you can participate by eating more meringues and buying a pet dove."

  2. 7
    Acronym of corporate responsibility. abbreviation, acronym, alt-of
  3. 8
    a bar of magnetic material (as soft iron) that passes through a coil and serves to increase the inductance of the coil wordnet
  4. 9
    In general usage, an essential part of a thing surrounded by other essential things.; The heart or inner part of a physical thing. countable, uncountable

    "Reindeer are well suited to the taiga’s frigid winters. They can maintain a thermogradient between body core and the environment of up to 100 degrees, in part because of insulation provided by their fur, and in part because of counter-current vascular heat exchange systems in their legs and nasal passages."

  5. 10
    the chamber of a nuclear reactor containing the fissile material where the reaction takes place wordnet
  6. 11
    In general usage, an essential part of a thing surrounded by other essential things.; The anatomical core, muscles which bridge abdomen and thorax. countable, uncountable
  7. 12
    (computer science) a tiny ferrite toroid formerly used in a random access memory to store one bit of data; now superseded by semiconductor memories wordnet
  8. 13
    In general usage, an essential part of a thing surrounded by other essential things.; The center or inner part of a space or area. countable, uncountable

    "the core of the square"

  9. 14
    the choicest or most essential or most vital part of some idea or experience wordnet
  10. 15
    The most important part of a thing or aggregate of things wherever located and whether of any determinate location at all; the essence. countable, uncountable

    "the core of a subject"

  11. 16
    the central meaning or theme of a speech or literary work wordnet
  12. 17
    The most important part of a thing or aggregate of things wherever located and whether of any determinate location at all; the essence.; A technical term for classification of things denoting those parts of a category that are most easily or most likely understood as within it.; The main and most diverse monophyletic group within a clade or taxonomic group. countable, uncountable
  13. 18
    a small group of indispensable persons or things wordnet
  14. 19
    The most important part of a thing or aggregate of things wherever located and whether of any determinate location at all; the essence.; A technical term for classification of things denoting those parts of a category that are most easily or most likely understood as within it.; The set of feasible allocations that cannot be improved upon by a subset (a coalition) of the economy's agents. countable, uncountable
  15. 20
    an organization founded by James Leonard Farmer in 1942 to work for racial equality wordnet
  16. 21
    The most important part of a thing or aggregate of things wherever located and whether of any determinate location at all; the essence.; A thematic aesthetic; objects related to a specific topic countable, uncountable

    "Photographs of cottagecore focuses on countrysides or forests."

  17. 22
    the center of an object wordnet
  18. 23
    particular parts of technical instruments or machines essential in function:; The portion of a mold that creates a cavity or impression within the part (casting or molded part) or that makes a hole in or through the part. countable, uncountable
  19. 24
    the central part of the Earth wordnet
  20. 25
    particular parts of technical instruments or machines essential in function:; Ellipsis of core memory (“magnetic data storage”). abbreviation, alt-of, countable, ellipsis, historical, informal, uncountable
  21. 26
    a cylindrical sample of soil or rock obtained with a hollow drill wordnet
  22. 27
    particular parts of technical instruments or machines essential in function:; An individual computer processor, in the sense when several processors (called cores or CPU cores) are plugged together in one single integrated circuit to work as one (called a multi-core processor). countable, uncountable

    "I wanted to play a particular computer game, which required I buy a new computer, so while the game said it needed at least a dual-core processor, I wanted my computer to be a bit ahead of the curve, so I bought a quad-core."

  23. 28
    particular parts of technical instruments or machines essential in function:; The material between surface materials in a structured composite sandwich material. countable, uncountable

    "a floor panel with a Nomex honeycomb core"

  24. 29
    particular parts of technical instruments or machines essential in function:; The inner part of a nuclear reactor, in which the nuclear reaction takes place. countable, uncountable

    "In the engine room, the changing angle dropped the melted core to the deck. The hot mass attacked the steel deck first, burning through that, then the titanium of the hull. Five seconds later the engine room was vented to the sea."

  25. 30
    particular parts of technical instruments or machines essential in function:; The central fissile portion of a fission weapon. countable, uncountable

    "In a hollow-core design, neutrons escape from the core more readily, allowing more fissile material to be used (and thus allowing for a greater yield) while still keeping the core subcritical prior to detonation."

  26. 31
    particular parts of technical instruments or machines essential in function:; A piece of ferromagnetic material (e.g., soft iron), inside the windings of an electromagnet, that channels the magnetic field. countable, uncountable
  27. 32
    particular parts of technical instruments or machines essential in function:; A hollow cylindrical piece of cardboard around which a web of paper or plastic is wound. countable, uncountable
  28. 33
    Hence particular parts of a subject studied or examined by technical operations, likened by position and practical or structural robustness to kernels, cores in the most vulgar sense above.; A tiny sample of organic material obtained by means of a fine-needle biopsy. countable, uncountable
  29. 34
    Hence particular parts of a subject studied or examined by technical operations, likened by position and practical or structural robustness to kernels, cores in the most vulgar sense above.; The bony process which forms the central axis of the horns in many animals. countable, uncountable
  30. 35
    Hence particular parts of a subject studied or examined by technical operations, likened by position and practical or structural robustness to kernels, cores in the most vulgar sense above.; A disorder of sheep caused by worms in the liver. countable, uncountable

    "[the skin of the sheep] is clear from cores and jogs under the jaws."

  31. 36
    Hence particular parts of a subject studied or examined by technical operations, likened by position and practical or structural robustness to kernels, cores in the most vulgar sense above.; The central part of a protein's structure, consisting mostly of hydrophobic amino acids. countable, uncountable
  32. 37
    Hence particular parts of a subject studied or examined by technical operations, likened by position and practical or structural robustness to kernels, cores in the most vulgar sense above.; A cylindrical sample of rock or other materials obtained by core drilling. countable, uncountable
  33. 38
    Hence particular parts of a subject studied or examined by technical operations, likened by position and practical or structural robustness to kernels, cores in the most vulgar sense above.; An atomic nucleus plus inner electrons (i.e., an atom, except for its valence electrons). countable, uncountable
Verb
  1. 1
    To remove the core of an apple or other fruit.
  2. 2
    remove the core or center from wordnet
  3. 3
    To cut or drill through the core of (something).

    "But the other thing to take into account is, when you look at the Katahdin and the Polyphemus, they both have their boiler plants pretty much amidships or slightly forward of amidships, which means that, in the event of a heat-lance strike on the boiler room, not only is that gonna core through the ship right at the center of mass, which is obviously bad for its continued structural stability, but the boilers going up is gonna incinerate pretty much anybody on the bridge, which is gonna leave it completely out of control, and is probably gonna break the ship clean in half right there and then, none of which really speaks to the ship's being able to continue onwards with enough momentum to take down a Martian tripod."

  4. 4
    To extract a sample with a drill.
Adjective
  1. 1
    Forming the most important or essential part. not-comparable

    "Privately held businesses may hold assets or have charges to their financial statements which are not core to their main business activity."

  2. 2
    Deeply and authentically involved in the culture surrounding the sport. not-comparable

    "Our interest is not in core skaters such as young males and pro skaters but the voices of those on the periphery of the subculture."

Slang
  1. 1
    Suffix used to label a themed style identity. slang, social-media, 2020s

    "That outfit is cottagecore."

Proper Noun
  1. 1
    Acronym of Congress of Racial Equality. US, abbreviation, acronym, alt-of

    "“I start heading back up to 125th and people are all buzzing, saying the police have beat up and arrested some CORE people.”"

  2. 2
    The birth name of Persephone/Proserpina, the queen of the Underworld/Hades, and goddess of the seasons and of vegetation. She is the daughter of Zeus and Demeter, and the wife of Hades. Greek
  3. 3
    Obsolete form of Korah. alt-of, obsolete
  4. 4
    Acronym of Center for Operations Research and Econometrics abbreviation, acronym, alt-of
  5. 5
    A female given name from Ancient Greek.
Show 6 more definitions
  1. 6
    Acronym of Consortium for Oceanographic Research and Education. abbreviation, acronym, alt-of
  2. 7
    A surname.
  3. 8
    Acronym of Council on Rehabilitation Education. abbreviation, acronym, alt-of
  4. 9
    A neighbourhood of San Diego, California, United States.
  5. 10
    Acronym of Computing Research and Education Association. abbreviation, acronym, alt-of
  6. 11
    An unincorporated community in Monongalia County, West Virginia, United States.

Synonyms

All synonyms
gistcentercruxessenceheartaccounting materiality

Antonyms

advanced societyecological unit boundaryelective courseexternal

Example

"This is the core of the problem."

Common questions

What does "core" mean?

In general usage, an essential part of a thing surrounded by other essential things.; The central part of a fruit, containing the kernels or seeds.

What is a synonym for "core"?

Common synonyms include: gist, center, crux, essence, heart, accounting materiality.

How do you use "core" in a sentence?

This is the core of the problem.

How do you pronounce "core"?

Pronounced /kɔː/.

Etymology

Etymology 1

From Middle English core, kore, coor (“apple-core, pith”), of obscure and uncertain origin. Possibly of native English origin, from Old English *cor, related to Old English *coruc, *corc (diminutive) (> Middle English cork, crok (“core of an apple or other fruit, heart of an onion”)) and Old English corn (“seed", also "grain”); or alternatively perhaps from Old French cuer (“heart”), from Latin cor (“heart”); or from Old French cors (“body”), from Latin corpus (“body”). Compare also Middle English colk, coke, coll (“the heart or centre of an apple or onion, core”), Dutch kern (“core”), German Kern (“core”). See also heart, corpse. Compare typologically Russian серде́чник (serdéčnik), сердцеви́на (serdcevína)) (akin to се́рдце (sérdce), cognate with heart, Latin cor).

Etymology 2

See corps.

Etymology 3

See chore.

Etymology 4

From Biblical Hebrew כֹּר (kōr).

Etymology 5

Possibly an acronym for cash on return.

Etymology 6

From -core, ultimately from Etymology 1.

Etymology 7

Learned borrowing from Ancient Greek κόρη (kórē, “maiden”).

Etymology 8

From French Coré.

More for "core"

Synonyms

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