In a general sense, a substance is a form of matter that has a specific composition and distinct properties. It can refer to a chemical element or compound, like water (H₂O), oxygen (O₂), or gold (Au), which maintains its identity and properties under certain conditions. Substances can be solids, liquids, or gases and can be either pure or a mixture of compounds. https://analysisandmetaphysics.com/index.php/journal/index