A vacuum is a region of space that is devoid of matter, meaning there are no atoms or molecules present.

Here's a breakdown:

* Matter: Anything that has mass and takes up space. This includes solids, liquids, gases, and even plasmas.

* Vacuum: A space where the pressure is significantly lower than atmospheric pressure, resulting in a near absence of matter.

While it's impossible to create a perfect vacuum in the real world, we can get very close. For example, the space between stars is a very good approximation of a vacuum.