DictionarynucleusEssential core
noun

nucleus

The central or essential part of something.

A few dedicated volunteers form the nucleus of our team.

Etymology

A kernel is the central substance within an enclosing shell. Nucleus extends that image to the essential core around which a larger thing is organized.

More examples

  • Her donated books provide the nucleus of the new library's collection.
  • The weekly market remains the nucleus of village life.
  • These neighborhood groups serve as nuclei for a wider movement.

Forms

nucleus · nuclei · nucleuses

Similar words

core
Emphasizes the essential part, without suggesting others gather around it.
heart
Often emphasizes a central source of vitality or meaning.
center
Can indicate location alone, without implying an essential part.