Amino Acid

organic compound from which proteins are made

group of organic compounds, basic constituents of proteins

In chemistry, an amino acid is a molecule that contains both amine and carboxyl functional groups. In biochemistry, this term refers to alpha-amino acids with the general formula H2NCHRCOOH, where R is an organic substituent. In the alpha amino acids, the amino and carboxylate groups are attached to the same carbon, which is called the α–carbon. The various alpha amino acids differ in which side chain (R group) is attached to their alpha carbon. They can vary in size from just a hydrogen atom in glycine, through a methyl group in alanine, to a large heterocyclic group in tryptophan.
See more at Wikipedia.org...

Amino acid /ami·no ac·id/ one of a class of organic compounds containing the amino and the carboxyl groups; they occur naturally in plant and animal [more]Amino acid - Community and Resources

Noun
1. organic compounds containing an amino group and a carboxylic acid group; "proteins are composed of various proportions of about 20 common amino acids"
(synonym) aminoalkanoic acid
(hypernym) organic compound
(hyponym) alanine
(substance-holonym) protein

One of the building blocks of protein. The term "amino acids" dates to the middle of the 19th century. The idea that amino acids are "Bausteine" (building stones) came from the Nobel Prize winning German biochemist Albrecht Kossel (1853-1927).