Guest
NerdDictionary The dictionary that writes itself

nuclei JUST WRITTEN FOR YOU

/ˈnjuː.kli.aɪ/ · nu·cle·i
noun
  1. The core or central part of something around which other elements are assembled. The library’s rare‑book collection formed the nucleus of the new research center.
  2. An initial part or version that will receive additions or expansions. The prototype served as the nucleus for a whole line of consumer gadgets.
  3. The massive, positively charged central part of an atom, composed of protons and neutrons. Scientists used a particle accelerator to probe the structure of atomic nuclei.
Did you know? The word ‘nucleus’ was first used in a biological context by Robert Brown in 1831, but its atomic meaning was popularized by Ernest Rutherford’s 1911 gold‑foil experiment.
Written by Lexi Wordsworth, Dictionary Editor 0 lookups Added Jul 15, 2026