This document defines several key terms related to food science and technology. It explains that food science is the study of the physical, biological, and chemical properties of food, while food technology is the application of science to food production, processing, packaging, and consumption. Food engineering applies engineering principles to transform raw materials into finished food products. The document also defines food, nutrition, nutrients, and feed. It classifies foods based on their origin as either plant-based or animal-based. Foods are also classified based on their pH value or acidity.