protein

Etymology

Suggested by Berzelius in a letter to Mulder, from French protéine and German Protein, both coined based on Ancient Greek πρωτεῖος (prōteîos, “primary”), from πρῶτος (prôtos, “first”).

noun

1. (biochemistry, 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.
   Meronym: amino acid
   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. (nutrition, uncountable) One of three major classes of food or source of food energy (4 kcal/gram) abundant in animal-derived foods (i.e. meat) and some vegetables, such as legumes.
3. (nutrition, countable) 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. 2015-04-29, Mandy Unanski Enright, “One Meal, Two Proteins”, in Nutrition Nuptials, archived from the original on 2019-04-11
   Served with seasoned rice, classic Greek salad, pita, tzatziki, choice of 2 proteins & 2 sides 2017, Daphne's California Greek, Catering Menu
   What should you get for lunch at a halal cart? Nutritionists explain how to pick a protein that isn't packed with calories and why you should beware the white sauce 2018-05-31, Mary Kekatos, Daily Mail