kernel

See also: kérnél

English

English Wikipedia has an article on:

kernel

Wikipedia

Etymology

From Middle English kernel, kirnel, kürnel, from Old English cyrnel, from Proto-West Germanic *kurnil, diminutive of Proto-Germanic *kurną (“seed, grain, corn”), equivalent to corn +‎ -le. Cognate with Yiddish קערנדל (kerndl), Middle Dutch kernel, cornel, Middle High German kornel. Related also to Old Norse kjarni (“kernel”).

Pronunciation

• (UK) IPA^(key): /ˈkɜː.nəl/
• (US) IPA^(key): /ˈkɝ.nəl/

• Audio (General Australian):

  (file)

• (Indic, rhotic) IPA^(key): /ˈkərnəl/, (without the fern–fir–fur merger) /ˈkɛrnəl/
• (Indic, non-rhotic) IPA^(key): /ˈkɜnəl/
• Homophone: colonel (most accents)
• Rhymes: -ɜː(ɹ)nəl

Noun

kernel (plural kernels)

1. The core, center, or essence of an object or system.

   Synonyms: crux, gist; see also Thesaurus:gist

   the kernel of an argument

2. (botany) The central (usually edible) part of a nut, especially once the hard shell has been removed.
3. (botany) A single seed or grain, especially of corn or wheat.
4. (botany, US) The stone of certain fruits, such as peaches or plums.
5. A small mass around which other matter is concreted; a nucleus; a concretion or hard lump in the flesh.
6. (computing) The central part of many computer operating systems which manages the system's resources and the communication between hardware and software components.

   Antonym: userland

   Hyponyms: microkernel, unikernel

   The Linux kernel is open-source.

7. (computing) The core engine of any complex software system.
8. (programming) The simplified input to an algorithm that has undergone kernelization.
9. (calculus) A function used to define an integral transform.

   The Dirichlet kernel convolved with a function yields its Fourier series approximation.

11. (mathematics, set theory, of a function ${\displaystyle f}$) The set of pairs of elements in the domain of ${\displaystyle f}$ which are mapped to the same value; the equivalence relation ${\displaystyle x\equiv y\iff f(x)=f(y)}$.

    If a function is continuous then its kernel is a closed set.

12. (mathematics, algebra, loosely, of a morphism ${\displaystyle f}$ between algebraic structures) The set of elements of the domain of ${\displaystyle f}$ which are mapped to an identity element.
    1. (mathematics, group theory, of a group homomorphism ${\displaystyle f\colon G\to H}$ between groups) The set of elements of ${\displaystyle G}$ which are mapped to the identity of ${\displaystyle H}$ (usually written as 0 in an additive group and as 1 in a multiplicative group).
    2. (mathematics, ring theory, of a ring homomorphism ${\displaystyle f\colon R\to S}$ between rings) The set of elements of ${\displaystyle R}$ which are mapped to the additive identity 0 of ${\displaystyle S}$.
    3. (mathematics, linear algebra, of a linear transformation ${\displaystyle f\colon M\to N}$ between modules or vector spaces) The set of elements of ${\displaystyle M}$ which are mapped to the additive identity 0 of ${\displaystyle N}$.

    Antonym: support

    Meronyms: root, zero

13. (mathematics, category theory, of a morphism ${\displaystyle f:X\to Y}$ in a category with zero morphisms) The equalizer of ${\displaystyle f}$ and the zero morphism from ${\displaystyle X}$ to ${\displaystyle Y}$, denoted ${\displaystyle \operatorname {ker} f}$.
    1. (mathematics, category theory) The source of ${\displaystyle \operatorname {ker} f}$, denoted ${\displaystyle \operatorname {Ker} f}$.
14. (mathematics, fuzzy set theory) The set of members of a fuzzy set that are fully included (i.e., whose grade of membership is 1).
15. (slang) The human clitoris.
    • 2014, Karyn Gerrard, Irene Preston, Lotchie Burton, et al: Summer Heat: 10 Spicy Romances That Sizzle:

      Using the blunt end of one of the vibraphone mallets, he pried open her folds. With the balled end of the other, he rhythmically rolled over her kernel.

16. (chemistry) The nucleus and electrons of an atom excluding its valence electrons.
    • 1916, Gilbert N. Lewis, “The Atom and The Molecule”, in Journal of the American Chemical Society, 38(4) p 768:

      1. In every atom is an essential kernel which remains unaltered in all ordinary chemical changes and which possesses an excess of positive charges corresponding in number to the ordinal number of the group in the periodic table to which the element belongs.

17. This term needs a definition. Please help out and add a definition, then remove the text {{rfdef}}.
    • 2025 December 11, Charlie Campbell, Andrew R. Chow and Billy Perrigo, “The Architects of AI Are TIME’s 2025 Person of the Year”, in Time‎:

      The drumbeat of warning that advanced AI could kill us all has mostly quieted; the “doomers” have been marginalized, now used by AI’s ruling class as a punch line. Yet even the most upbeat AI leaders are quick to offer kernels of warning.

Derived terms

• cokernel
• enkernel
• exokernel
• grape kernel
• KERNAL
• kernelate
• kernel corn
• kernel cowry, kernel cowrie (Nucleolaria nucleus)
• kernel function
• kernel hacker
• kernelisation
• kernelization
• kernelize
• kernelless
• kernelly
• kernel of truth
• kernel pair
• kernel panic
• kernel sentence
• kernel space
• multikernel
• nanokernel
• palm kernel
• palm kernel oil
• pine kernel
• positive-definite kernel
• subkernel
• tree kernel
• waxing kernel

Descendants

• → Japanese: カーネル (kāneru)

Translations

core or essence of an object or system

Armenian: միջուկ (hy) (miǰuk), կորիզ (hy) (koriz) Bulgarian: ядро́ (bg) n (jadró), съ́щност (bg) f (sǎ́štnost) Chinese: Mandarin: 核心 (zh) (héxīn) Finnish: ydin (fi) French: fond (fr) m, cœur (fr) m Galician: cerne (gl) m Georgian: მარცვალი (marcvali), გული (guli), არსი (arsi) German: Kern (de) m Greek: πυρήνας (el) m (pyrínas) Irish: eithne f Italian: nucleo (it) m, nocciolo (it) m Japanese: 核心 (ja) (かくしん, kakushin) Korean: 핵심(核心) (ko) (haeksim) Macedonian: јадро n (jadro), срж f (srž) Maori: karihi Polish: trzon (pl) m, rdzeń (pl) m, sedno (pl) n Portuguese: cerne (pt) m Russian: суть (ru) f (sutʹ), су́щность (ru) f (súščnostʹ) Scottish Gaelic: eitean m, cridhe m Sorbian: Lower Sorbian: jědro n Spanish: núcleo (es) m Swedish: kärna (sv) ? Turkish: öz (tr) Yiddish: קערן m (kern)

central part of a nut

Azerbaijani: özək (az) Bulgarian: я́дка (bg) f (jádka) Czech: jádro (cs) n Finnish: pähkinä (fi) French: amande (fr) f, cerneau (fr) m Georgian: გული (guli) German: Kern (de) m Greek: πυρήνας (el) m (pyrínas) Hawaiian: ʻanoʻano Icelandic: kjarni (is) m Ingrian: toomi Italian: gheriglio (it) m Japanese: 仁 (ja) (じん, jin) Macedonian: срцевина f (srcevina) Maori: kākano (mi), karihi, kiko, kikokiko Old English: cyrnel m Portuguese: miolo (pt) m Russian: ядро́ (ru) n (jadró), сердцеви́на (ru) f (serdcevína) (fruit) Samoan: ʻaʻano Scottish Gaelic: eitean m Sorbian: Lower Sorbian: jědro n Spanish: almendra (es) f, núcleo (es) m Swedish: kärna (sv) ? Tongan: kano Turkish: göbek (tr) Yiddish: קערנדל n (kerndl)

single seed of corn or wheat

Bulgarian: зърно́ (bg) n (zǎrnó) Dutch: graan (nl) n Finnish: jyvä (fi) French: grain (fr) m Georgian: მარცვალი (marcvali) Gothic: 𐌺𐌰𐌿𐍂𐌽𐍉 n (kaurnō) Greek: Ancient: κόκκος m (kókkos) Italian: chicco (it) m Macedonian: зрно n (zrno) Polish: ziarno (pl) n Portuguese: grão (pt) m Russian: зерно́ (ru) n (zernó), зёрнышко (ru) n (zjórnyško) Scottish Gaelic: sìol m Spanish: grano (es) m Swedish: korn (sv) ? Tarifit: taɣyašt f Turkish: tane (tr) Yiddish: קערנדל n (kerndl)

(US) stone of certain fruits, such as peaches or plums

Armenian: կորիզ (hy) (koriz) Bashkir: һөйәк (höyək) Bulgarian: костилка (bg) f (kostilka) Czech: pecka (cs) f Finnish: kivi (fi) French: noyau (fr) m Greek: πυρήνας (el) m (pyrínas), κουκούτσι (el) n (koukoútsi) Indonesian: kernel Italian: nocciolo (it) m Kyrgyz: өзөк (ky) (özök) Macedonian: голушка f (goluška), коска (mk) f (koska) Polish: pestka (pl) f Portuguese: caroço (pt) m Russian: ко́сточка (ru) f (kóstočka) Spanish: hueso (es) m, núcleo (es) m Turkish: çekirdek (tr)

(computing) central part of many computer operating systems

Arabic: نَوَاة f (nawāh) Gulf Arabic: نواة f (nuwāt) Bulgarian: ядро (bg) n (jadro) Czech: jádro (cs) n Danish: kerne c Finnish: käyttöjärjestelmäydin, ydin (fi), kerneli French: noyau (fr) m German: Betriebssystemkern m, Kernel (de) m Greek: πυρήνας (el) m (pyrínas) Icelandic: kjarni (is) m, stýrikjarni m Indonesian: kernel Italian: kernel (it) m Japanese: カーネル (かーねる, kāneru) Korean: 커널 (keoneol) Kyrgyz: өзөк (ky) (özök), дан (ky) (dan) Macedonian: јадро n (jadro) Malay: inti (ms) Polish: jądro (pl) n, jajko (pl) n Portuguese: kernel (pt) m, núcleo (pt) m Russian: ядро́ (ru) n (jadró) Spanish: núcleo (es) m, granelo m Swedish: operativsystemkärna c, kärna (sv) c Turkish: çekirdek (tr) Vietnamese: nhân (vi)

(mathematics, algebra) set of elements mapped to zero

Bulgarian: ядро (bg) n (jadro) Czech: jádro (cs) n Danish: kerne c Dutch: kern (nl) m or f Finnish: nolla-avaruus, ydin (fi) French: noyau (fr) m German: Kern (de) m Greek: πυρήνας (el) m (pyrínas) Hungarian: mag (hu) Italian: nucleo (it) m Polish: jądro (pl) n Portuguese: núcleo (pt) m Russian: ядро́ (ru) n (jadró) Spanish: núcleo (es) m

(mathematics, fuzzy set theory) Set of members of a fuzzy set that are fully included

Bulgarian: please add this translation if you can Finnish: ydin (fi)

The translations below need to be checked and inserted above into the appropriate translation tables. See instructions at Wiktionary:Entry layout § Translations.

Translations to be checked

Esperanto: (please verify) kerno (eo) Georgian: (please verify) მარცვალი (marcvali)

Verb

kernel (third-person singular simple present kernels, present participle (US) kerneling or (UK) kernelling, simple past and past participle (US) kerneled or (UK) kernelled)

1. To enclose within a kernel
2. To crenellate

Anagrams

• kleren