nucleus

• Nom désignant la partie centrale et la plus importante d'un objet, d'un mouvement ou d'un groupe, formant la base de son activité et de sa croissance. En biologie, c'est un organite dense dans la cellule contenant le matériel génétique ; en physique, le noyau chargé positivement de l'atome ; en astronomie, la partie centrale solide d'une comète ; en anatomie, un amas de cellules nerveuses ; dans l'usage courant, un petit groupe indispensable de personnes ou de choses.

A noun referring to the central and most important part of an object, movement, or group, forming the basis for its activity and growth. In biology, it is the dense organelle in a cell containing genetic material; in physics, it is the positively charged core of an atom; in astronomy, it is the solid central part of a comet; in anatomy, it is a mass of nerve cells; and in general use, it denotes a small, indispensable group of people or things.

pluriel irrégulier

1. Cell nucleusB2formalscientific

   A membrane-bound organelle within a cell that contains the genetic material (DNA and RNA) and controls growth and reproduction.

   noyau cellulaire

   • The nucleus directs all cellular activities by regulating gene expression.
   • Scientists extracted the nucleus from the cell for further analysis.
   • The nucleus is often called the control center of the cell.

   Synonymeskaryon

2. Atomic nucleusB2formalscientific

   The small, dense, positively charged central core of an atom, composed of protons and neutrons.

   Noyau atomique

   • The atomic nucleus contains nearly all the mass of the atom.
   • Nuclear fission involves splitting the nucleus of an atom.
   • Electrons orbit around the nucleus at various energy levels.

3. Core groupB2formal

   A small, essential group of people or things that form the central part of something larger.

   noyau (groupe central)

   • A nucleus of experienced staff remained after the reorganization.
   • The club's nucleus consists of five founding members.
   • The project's nucleus is a team of dedicated volunteers.

   Synonymescentercoreessencefocushearthubkernelnub

4. Comet nucleusC1formalscientific

   The solid, central part of a comet's head, composed of ice, dust, and frozen gases, which vaporizes near the sun to form the coma and tail.

   Noyau cométaire

   • The comet's nucleus is only a few kilometers in diameter.
   • As the comet approaches the sun, its nucleus heats up and releases gas.
   • Space probes have captured images of a comet's nucleus.

   Synonymescore

5. Neural nucleusC1formalmedical

   A distinct cluster of nerve cell bodies within the brain or spinal cord, identifiable by histology.

   Noyau nerveux

   • The thalamus contains several important neural nuclei.
   • Damage to a specific neural nucleus can affect motor control.
   • The brainstem has nuclei that regulate vital functions.

6. Lens nucleusC1formalmedical

   The central, densest part of the eye's lens, surrounded by the lens cortex.

   Noyau du cristallin

   • Cataracts often form in the nucleus of the lens.
   • The lens nucleus becomes harder with age.
   • Surgery may involve removing the cloudy lens nucleus.