Matter is any substance that has mass and occupies space by having volume. It includes all everyday objects made up of atoms, which themselves consist of subatomic particles like protons, neutrons, and electrons

. Matter can exist in various states or phases, including solids, liquids, gases, and plasma

. At a fundamental level, matter is composed of elementary particles such as quarks and leptons. Quarks combine to form protons and neutrons, while leptons include electrons. Atoms, which are made of these particles, combine to form molecules, and these molecules make up the bulk of matter we encounter daily

. Matter differs from energy phenomena like light or heat because it has rest mass and takes up space, whereas massless particles such as photons do not qualify as matter

. In summary:

• Matter : Anything with mass and volume that occupies space.
• Composition : Made of atoms (protons, neutrons, electrons) and ultimately elementary particles (quarks, leptons).
• States : Solid, liquid, gas, plasma.
• Examples : Air, water, solids, living organisms, etc.

This definition aligns with both classical physics and modern understanding of particle physics