1. A configuration that shows the way in which the electrons in an atom occupy, in order of increasing energy, the available orbitals and spin states.
2. The orbital arrangement of an atom's electrons.

Negatively charged electrons are attracted to a positively charged nucleus to form an atom or an ion.

3. The arrangement of electrons in an atom, molecule, or other physical structure; such as, a crystal.
4. The specific distribution of electrons in atomic orbitals of atoms or or ions.