Physico-chemical describes phenomena involving both physical and chemical changes, the combined transformations that define most food processing. Baking a loaf is physico-chemical: heat drives physical changes like starch gelatinisation, protein denaturation, and moisture migration alongside chemical reactions including Maillard browning, caramelisation, and fermentation chemistry. Food scientists use the term to frame analyses that measure both dimensions, texture profile analysis alongside pH and composition, or to describe properties like emulsification that depend on molecular chemistry expressing itself in physical structure. Stability testing, shelf-life modelling, and novel process validation all operate in this combined space. The hyphenated term resists the artificial separation of physics and chemistry, insisting that in real foods, structure and reaction are two faces of the same transformation.