nucleus Definition

nucleus
noun nuclei

1. physics.
The positively charged tiny central part of an atom, consisting of neutrons and protons and surrounded by electrons.
2. biol.
The central part of a plant or animal cell, containing genetic material.
3. chem.
A stable group of atoms in a molecule acting as a base for the formation of compounds.
4. chem.
A small particle acting as the basis on which crystals can grow.
5. A core round which things accumulate.

Thesaurus: essence, core, gist, kernel, crux, centre, hub, pivot, focus, matter, nub.

Etymology: 18c, meaning ‘a central part': Latin, meaning ‘kernel'.