Anything that has mass and occupies space is referred to as matter. This includes all physical substances we encounter in our daily lives, ranging from solid objects like books and furniture to liquids like water and gases like air.
In scientific terms, matter is composed of particles, which include atoms and molecules. These particles have mass, which gives matter its weight, and they take up space, which is defined in three-dimensional terms. Thus, whether you’re holding a rock or observing the steam from a boiling pot, both are forms of matter since they have mass and take up space.