DictionaryAI

core

KOR/kɔɹ/UKKAW/kɔː/

Noun pluralcores

29 meanings of core

Practice

  1. 1
    most importantadjective
    Forming the most important or essential part of something.

    Trust remains a core principle of the whole agreement.

    The committee focused on the core issues before anything else.

    UsageUsually before a noun (core subjects). After a linking verb, it can be followed by to: core to the business.

    Similarcentral, key, fundamental, essential, basic

    Oppositeperipheral, secondary, marginal, minor

  2. 2
    central ideanouncountable or uncountable
    The most important part of something or a group of things: its essence.

    The core of her argument rested on a single statistic.

    At the core of the movement lay a demand for fairness.

    UsageOften at the core of something; to the core means completely: rotten to the core.

    Similaressence, heart, crux, nub, kernel

    Note

    Here the word leaves physical position behind entirely. Its favorite frame is at the core of: Nathan Rabin, reviewing Men in Black 3 for The Onion AV Club in 2012, wrote of 'the craggy stoicism at the character's core.' Common core is a settled pairing too, as in a common core of English words. The botanist's and the economist's technical uses both build on this abstract sense.

    Checked 31 Oct 2026 · 4 facts

    • Nathan Rabin reviewed Men in Black 3 for The Onion AV Club in 2012. en.wiktionary.org
    • Rabin's review contains the quoted wording. avclub.com
    • The botanical technical sense is classified under the abstract sense. en.wiktionary.org
    • The economic technical sense is classified under the abstract sense. en.wiktionary.org
  3. 3
    processor (chip)nouncountable or uncountable
    An individual processor combined with others on a single integrated circuit to function together as one multi-core processor.

    The operating system spread the workload across every available core.

    Developers optimized the program to use more than one core.

    UsageIn compounds such as dual-core processor and quad-core processor, the first part gives the number of cores.

    Note

    Each core runs its own stream of instructions while sharing one integrated circuit with the others. That is why software has to be written to spread its work across several cores before it can use more than one of them at a time.

  4. 4
    nouncountable or uncountable
    The central or innermost part of an object, area, or space, as distinct from its outer parts.

    Traffic clogs the core of the financial district every morning.

    The storm's most violent winds spun around its core.

    Oppositeperiphery, edge, outskirts, fringe

    Note

    Here the core is somewhere you could stand. Walter Raleigh writes of 'the core of the square' in The Historie of the World (1614), and the sense still serves for districts and storms. Because an open space has no outer layer to hide behind, the word marks the middle rather than a hidden inside. When the center is a matter of importance rather than position, the essence meaning has taken over.

    Checked 31 Oct 2026 · 2 facts

  5. 5
    stomach musclesnouncountable or uncountable
    The muscles of the trunk, chiefly those of the abdomen, lower back, and pelvis, that steady the spine and body during movement.

    The trainer designed exercises to engage the core throughout the routine.

    Runners with a weak core often struggle to hold their posture.

    UsageUsually singular (your core, a weak core) or before a noun (core strength, core exercises).

    Similarmidsection

    Note

    It names a working group of muscles rather than a single one. The transverse abdominis, multifidus and obliques are among them, spanning the abdomen, lower back and pelvis. Together they steady the spine and pass force between the upper and lower body.

    Checked 2 Nov 2026 · 4 facts

  6. 6
    nouncountable or uncountable
    A cylindrical sample of rock, ice, tissue, or other material, removed by drilling or with a hollow needle for examination.

    The team labeled each core before storing it for analysis.

    Ice cores from the glacier revealed centuries of climate data.

    Similarsample

  7. 7
    nuclear reactornouncountable or uncountable
    The central region of a reactor that houses the fuel and sustains the nuclear reaction.

    Operators monitored the core for sudden temperature spikes.

    A loss of coolant exposed part of the core to the air.

    Note

    Fuel assemblies, moderator and control rods all sit here. This is where the controlled fission chain reaction produces most of the system's heat. The word's most dramatic collocation is a melted core. In Tom Clancy's The Hunt for Red October (1984), a melted reactor core drops to the deck and burns through the steel and then the titanium hull.

    Checked 31 Oct 2026 · 5 facts

    • The reactor core contains fuel assemblies, moderator and control rods. energy.gov
    • The controlled fission chain reaction in the core supplies the system's heat. imeche.org
    • Tom Clancy wrote The Hunt for Red October. usni.org
    • The Hunt for Red October was first published in 1984. archive.org
    • The novel describes a melted reactor core dropping onto a steel deck and burning through it and the titanium hull. johnesimpson.com

Practice

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Origins

Meanings 1–9, 11–13

Middle English had core, kore, coor ("apple-core, pith"), but where it came from is obscure and uncertain. It may be a native English word related to Old English corn ("seed, grain"). Other possible sources are Old French cuer ("heart"), from Latin cor, and Old French cors ("body"), from Latin corpus.

Meaning 10

From -core, ultimately derived from Etymology 1.

Checked 31 Oct 2026 · 2 facts