The region where an electron is most likely to be found is called an electron cloud or orbital.

Here's a breakdown:

* Electron Cloud: This is a visual representation of the probability of finding an electron in a particular region around the nucleus. It's not a solid object, but rather a fuzzy, three-dimensional space where the electron is most likely to be located.

* Orbital: This is a more specific term describing a specific region of space around the nucleus where an electron has a high probability of being found. Each orbital has a distinct shape and energy level.

The exact shape and size of an electron cloud or orbital depend on the energy level and type of orbital (s, p, d, f).