essential amino acid es·sen·tia·laminoacid uncommon noun 1. an amino acid that is required by animals but that they cannot synthesize; must be supplied in the diet Synonymsessential amino acid Related words Broader terms amino acid Narrower terms argininehistidineisoleucineleucinelysinemethioninephenylalaninethreonine WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.
