• (RP) enPR: kô, IPA: /kɔː/
• (America) enPR: kôr, IPA: /koɹ/, [kʰo̞ɹ]
• (rhotic, non-horse-hoarse) IPA: /ko(ː)ɹ/
• (non-rhotic, non-horse-hoarse) IPA: /koə/

From Middle English core, kore, coor, of obscure and uncertain origin.

core

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

      the core of an apple or quince

   2. The heart or inner part of a physical thing.
   3. The Core (anatomy), muscles which bridge abdomen and thorax.
   4. The center or inner part of a space or area.
      • 1614, Walter Ralegh [i.e., Walter Raleigh], The Historie of the World […], London: […] William Stansby for Walter Burre, […], →OCLC ↗, (please specify |book=1 to 5):

        the core of the square

2. The most important part of a thing or aggregate of things wherever located and whether of any determinate location at all; the essence.

   the core of a subject

   1. A technical term for classification of things denoting those parts of a category that are most easily or most likely understood as within it.
      1. (botany) Used to designate the main and most diverse monophyletic group within a clade or taxonomic group.
      2. (game theory) The set of feasible allocations that cannot be improved upon by a subset (a coalition) of the economy's agents.
   2. (art) A thematic aesthetic; objects related to a specific topic

      Photographs of cottagecore focuses on countrysides or forests.

3. particular parts of technical instruments or machines essential in function:
   1. (engineering, manufacturing) 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.

      Coordinate term: cavity

   2. (computing, informal, historical) Ellipsis of core memory; magnetic data storage.
   3. (computer hardware) 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).

      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.

   4. (engineering) The material between surface materials in a structured composite sandwich material.

      a floor panel with a Nomex honeycomb core

   5. (engineering, nuclear physics) The inner part of a nuclear reactor, in which the nuclear reaction takes place.
   6. (military) The central fissile portion of a fission weapon.

      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.

   7. A piece of ferromagnetic material (e.g., soft iron), inside the windings of an electromagnet, that channels the magnetic field.
   8. (printing) A hollow cylindrical piece of cardboard around which a web of paper or plastic is wound.
4. 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.
   1. (medicine) A tiny sample of organic material obtained by means of a fine-needle biopsy.
   2. The bony process which forms the central axis of the horns in many animals.
   3. A disorder of sheep caused by worms in the liver.
   4. (biochemistry) The central part of a protein's structure, consisting mostly of hydrophobic amino acids.
   5. A cylindrical sample of rock or other materials obtained by core drilling.
   6. (physics) An atomic nucleus plus inner electrons (i.e., an atom, except for its valence electrons).

• (The most important part of a thing) crux, gist; See also Thesaurus:gist

• French: trognon, noyau, cœur
• German: Kerngehäuse
• Italian: nocciolo
• Portuguese: caroço
• Russian: ядро́
• Spanish: corazón

• French: cœur
• German: Kern
• Italian: nocciolo, cuore
• Portuguese: cerne, miolo
• Russian: сердцеви́на
• Spanish: núcleo, centro

• French: centre, cœur
• German: Kern
• Italian: anima, centro, nucleo
• Portuguese: cerne, núcleo
• Russian: ядро́
• Spanish: núcleo, centro

• French: cœur
• German: Kern
• Italian: essenza, fondamento
• Portuguese: âmago, cerne, coração, essência
• Russian: суть
• Spanish: esencia

• Russian: сердцеви́на

• German: Kernspeicher

• French: cœur
• German: Kern
• Portuguese: core, núcleo
• Russian: ядро́
• Spanish: núcleo

• Italian: caparra

• French: carotte
• Russian: керн

• French: mandrin

• Italian: nucleo
• Russian: атомный остов

• French: noyau
• Italian: nucleo
• Russian: магнитопровод

core (not comparable)

1. Forming the most important or essential part.
2. (board sports) Deeply and authentically involved in the culture surrounding the sport.
   • 2022, Malcolm Gladwell, The Tipping Point: How Little Things Can Make a Big Difference:

     We had a segmentation strategy, where the small, independent core skate shops — the three hundred boutiques around the country who really created us — had a certain product line that was exclusive to them. […] We said to the core shops, you don't have to compete with the malls.

   • 2023, Mari Kristin Sisjord, Women in Snowboarding:

     […] which provoked resistance among the 'core' snowboarders.

core (cores, present participle coring; simple past and past participle cored)

1. To remove the core of an apple or other fruit.
2. To cut or drill through the core of (something).
3. To extract a sample with a drill.

• Spanish: descorazonar

See corps

core (plural cores)

1. (obsolete) A body of individuals; an assemblage.
   • 1622, Francis, Lord Verulam, Viscount St. Alban [i.e. Francis Bacon], The Historie of the Raigne of King Henry the Seventh, […], London: […] W[illiam] Stansby for Matthew Lownes, and William Barret, →OCLC ↗:

     He was in a core of people.

See chore.

core (plural cores)

1. A miner's underground working time or shift.

• Italian: turno

From hbo כֹּר.

core (plural cores)

1. (historical units of measure) Alternative form of cor: a former Hebrew and Phoenician unit of volume.

Possibly an acronym for cash on return.

core (plural cores)

1. (automotive, machinery, aviation, marine) 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.

From -core, ultimately from Etymology 1.

core (plural cores)

1. (neologism) An aesthetic ending in the suffix -core, such as cottagecore, normcore, etc.
   • 2021 February 5, Kaitlyn Tiffany, “Cottagecore Was Just the Beginning”, in The Atlantic‎, Washington, D.C.: The Atlantic Monthly Group, →ISSN ↗, →OCLC ↗, archived from the original ↗ on 5 February 2021:

     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.

1. Acronym of corporate responsibility

1. Acronym of Congress of Racial Equality
2. Acronym of Center for Operations Research and Econometrics
3. Acronym of Consortium for Oceanographic Research and Education
4. Acronym of Council on Rehabilitation Education
5. Acronym of Computing Research and Education Association

1. (Greek god) 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.
2. A female given name
3. Surname.
4. A neighbourhood in San Diego, California.
5. An ucomm in Monongalia County, West Virginia.

From French Coré.

1. Obsolete form of Korah