noun, plural: matters
(1) The material of the universe, especially one that occupies space and has mass
(2) The substance that make up an object
(3) (archaic) A discharge or waste from a living organism (e.g. pus or feces)
In general science contexts, the term matter refers to anything (a substance or a material) from which objects are made. Generally, matter is made up of atoms, has (rest) mass, and occupies space (volume). There are basically four phases or states of matter: (1) solid, (2) liquid, (3) gas, and (4) plasma. A solid matter is characterized by its definite shape and volume. The molecules that make up a solid matter are closely and tightly packed thus giving it a particular shape. A liquid matter is characterized by its lack of a definite shape but with a definite volume. The molecules that make up a liquid matter are tiny vibrating particles that take up the shape of its container. Water is the most common form of a liquid on earth. Liquids flow and most of them resist compression. Gas is a matter that is made up of molecules that are distant from each other, thus, it does not have a fixed shape and most gases are not visible to its observer. Plasma is an ionized state of matter. It is made up of partially ionized gas.
Word origin: Latin materia (stuff, material), of Latin mater (mother)