mac·ro·nu·tri·ent ˌmakrōˈn(y)o͞otrēənt/ noun BIOLOGY plural noun: macronutrients a substance required in relatively large amounts by living organisms, in particular. a type of food (e.g., fat, protein, carbohydrate) required in large amounts in the human diet. a chemical element (e.g., potassium, magnesium, calcium) required in large amounts for plant growth and development. ARE YOU DYING DURING […]