The term that defines areas of electron density around a nucleus is orbitals.

Here's why:

* Orbitals represent regions of space around the nucleus where there is a high probability of finding an electron. They are not fixed paths like the orbits of planets around the sun.

* Electron density refers to the likelihood of finding an electron in a particular region of space.

* Atomic orbitals are described by quantum numbers, which determine their shape, size, and energy level.

So, orbitals are the specific areas of electron density around the nucleus, not just any general region of space.