nucleus

Etymology

Borrowed from Latin nucleus (“kernel, core”), a diminutive of nux (“nut”). The earliest uses refer to the head of a comet and the kernel of a seed, both recorded in Lexicon Technicum in 1704. The sense in atomic physics was coined by English scientist Michael Faraday in 1844 in a theoretical meaning.

noun

1. The core, central part of something, around which other elements are assembled.
2. An initial part or version that will receive additions.
   This collection will form the nucleus of a new library.
3. (chemistry, physics) The massive, positively charged central part of an atom, made up of protons and neutrons.
   Meronyms: proton, neutron, electron
4. (cytology) A large membrane-enclosed organelle found in eukaryotic cells which contains genetic material.
5. (neuroanatomy) A ganglion, cluster of many neuronal bodies where synapsing occurs.
6. (phonetics, phonology) The central part of a syllable, most commonly a vowel.