Essential

Name:
Essential
Detailed information:
(1) Containing the characteristic odor or flavor, (i.e., the essence) of the original flower or fruit: an essential oil, usually obtained by steam distillation of the flowers or leaves or cold-pressing of the skin. (2) As applied to certain amino acids, fatty acids, and vitamins, this term is used by biochemists to mean that the compound in question is a necessary nutritional factor that is not synthesized within the body of the animal and thus must be obtained from external sources. Eight amino acids are classified as essential on this basis.See Amino Acid.