proteins

Noun

protein (countable and uncountable, plural proteins)

1. (countable) Any of numerous large, complex naturally-produced molecules composed of one or more long chains of amino acids, in which the amino acid groups are held together by peptide bonds.
   • Proteins carry out the bulk of cellular functions, including relaying signals, providing structural support, and accelerating biochemical reactions.2010, Siddhartha Mukherjee, The Emperor of All Maladies, Fourth Estate (2011), page 534
2. (uncountable, nutrition) One of three major classes of food or source of food energy (4 kcal/gram) abundant in animal-derived foods (meat) and some vegetables, such as legumes.
   • Along with carbohydrates and fat, protein is one of the three main macronutrients that make up our diet. Furthermore, it is the only macronutrient that supplies us with amino acids, making it essential for survival.2025 April 15, Andrea Kane, “How to boost protein in your diet, without losing other nutrients. 5 tips from an expert”, in CNN
3. (countable, nutrition) A food rich in protein, often a meat or meat substitute.
   • The preparation style should be the same for both proteins so that the side dishes compliment the meal.2015 April 29, Mandy Unanski Enright, “One Meal, Two Proteins”, in Nutrition Nuptials, archived from the original on 11 Apr 2019