(nuclei)
1.
The ~ of an atom or cell is the central part of it.
Neutrons and protons are bound together in the ~ of an atom.
N-COUNT: usu with supp
2.
The ~ of a group of people or things is the small number of members which form the most important part of the group.
The Civic Movement could be the ~ of a centrist party of the future.
= core
N-COUNT: usu the N of n