[ kawr, kohr ]
See synonyms for core on
  1. the central part of a fleshy fruit, containing the seeds.

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

  1. 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.

  2. (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.

  3. the inside wood of a tree.

  4. Anthropology. a lump of stone, as flint, from which prehistoric humans struck flakes in order to make tools.: Compare flake tool.

  5. Carpentry.

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

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

  6. Engineering. kern2.

  7. Metallurgy.

    • a thickness of base metal beneath a cladding.

    • the softer interior of a piece of casehardened metal.

    • 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.

  8. 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.: Compare crust (def. 6), mantle (def. 3).

  9. Also called reactor core .Physics. the region in a reactor that contains its fissionable material.

  10. Computers.

    • 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.

    • Also called main memory, RAM . a term used to refer to main memory, though no longer made from from coils of ferromagnetic material.

  11. Ropemaking. heart (def. 16).

  12. Phonetics. the final segment of a syllable beginning with the vowel and including any following consonants; the nucleus plus the coda.: Compare onset (def. 3).

  13. 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),cored, cor·ing.
  1. to remove the core of (fruit).

  2. to cut from the central part.

  1. to remove (a cylindrical sample) from the interior, as of the earth or a tree trunk: to core the ocean bottom.

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

  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.

Origin of core

First recorded in 1350–1400; 1945–50 for def. 11; Middle English; origin uncertain; perhaps from Old French cors “body,” from Latin corpus

Other words for core

Other words from core

  • coreless, adjective

Words that may be confused with core

Words Nearby core

Other definitions for core (2 of 5)

[ kawr, kohr ]

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

Origin of core

First recorded in 1620–30; alteration of Middle English chor(e) “group, company; choir”; see chorus

Other definitions for Core (3 of 5)

[ kawr-ee, kohr-ee ]

  1. Classical Mythology. Kore.

Other definitions for CORE (4 of 5)


or C.O.R.E.

[ kawr, kohr ]

  1. Congress of Racial Equality.

Other definitions for -core (5 of 5)


  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.: normcore; queercore; emocore.

  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.: grandmacore; cottagecore. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use core in a sentence

British Dictionary definitions for core (1 of 3)


/ (kɔː) /

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

    • the central, innermost, or most essential part of something: the core of the argument

    • (as modifier): the core meaning

  1. 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

  2. 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

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

  4. 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

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

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

  7. computing

    • one of several processing units working in parallel in a computer

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

    • short for core store

    • (as modifier): core memory

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

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

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

Origin of core

C14: of uncertain origin

Derived forms of core

  • coreless, adjective

British Dictionary definitions for CORE (2 of 3)


/ (kɔː) /

n acronym for(in the US)
  1. Congress of Racial Equality

British Dictionary definitions for -core (3 of 3)


n combining form
  1. indicating a type of popular music: dancecore

adj 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

Scientific definitions for core


[ 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.

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

  2. 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.

  3. 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. See more at core tool.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Cultural definitions for core


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

Notes for core

The core is made primarily of iron and nickel and has two parts — an inner solid core and an outer liquid core.

Notes for core

The mantle is the layer of the Earth that overlies the core.

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Other Idioms and Phrases with core


see rotten to the core.

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.