Volume

Volume is the amount of space something takes up. Therefore anything that takes up space has volume.

As with mass, gases tend to muddle people when it comes to volume. If you walked into a house under construction, you might say that all of the rooms are empty, but of course they aren’t—they’re filled with air. You can easily prove that they are by ... breathing. You can show that air takes up space simply by inflating a balloon. Even better, push an inverted cup under water. The inside of the cup will stay dry. This is because the air in the cup fills the space of the cup and will not allow the water into the cup.

Light on the other hand can "fill a room" but it doesn't actually take up any space. The room size doesn't change whether the lights are on or off. Another way to show this is to point a flashlight or a laser pointer into a balloon. No matter how long you leave it there, pouring light into the balloon, the balloon will never expand or be filled.

Having volume is half of the definition of matter. The other half is having mass.