10 letters · 20 points in Scrabble
noun an amino acid that occurs in proteins; is essential for growth and normal metabolism; a precursor of niacin
originEtymology tree German Tryptophanbor. English tryptophan From German Tryptophan, from Ancient Greek φαίνω (phaínō, “to appear”).
Etymology from Wiktionary, CC BY-SA 3.0