Tryptophan
WordNet
noun
(1) An amino acid that occurs in proteins; is essential for growth and normal metabolism; a precursor of niacin
WiktionaryText
Noun
- An essential amino acid having an indole side chain; it is present in many foods, especially chocolate, oats, bananas and milk; it is essential for normal growth and development and is the precursor of serotonin and niacin.