Definition of Hyaluronic acid

Hyaluronic acid: A viscous slippery substance that lubricates the joints, maintains the shape of the eyeballs, and is a key component of connective tissue. On a more technical level, hyaluric acid is an glycosaminoglycan (formerly called a mucopolysaccharide), a long unbranched polysaccharide (complex sugar), composed of repeating dimeric units of glucuronic acid and N acetyl glucosamine.