Here's why:

* Plasma is a state of matter where the atoms are stripped of their electrons, resulting in a mixture of ions and free electrons. This occurs at extremely high temperatures, typically millions of degrees.

* While we often think of "gas" as being a distinct state of matter, at incredibly high temperatures, the gas becomes so energized that it transitions into a plasma.

Examples of Plasma:

* The sun and other stars

* Lightning

* Fluorescent lights

* Some types of welding arcs

So, while "very hot gas" isn't technically wrong, "plasma" is a more specific and accurate term to describe such a state.