The word "agar" comes from the Malay word agar-agar (meaning jelly). It is also known as kanten, China grass, or Japanese isinglass.
According to the European Commission Directive 2008/84/EC, Agar (E406) is defined as a hydrophilic colloidal polysaccharide consisting mainly of D-galactose units. It is extracted from certain natural strains of marine algae of the families Gelidiaceae and Sphaerococcaceae and related red algae of the class Rhodophyceae.

AGAR is used as stabilizing agent, thickening agent, gelling agent, floating agent, clarifying agent etc.
The gelling agent is an unbranched polysaccharide obtained from the cell walls of some species of red algae, primarily from the genera Gelidium and Gracilaria, or seaweed
AGAR is mainly used as an ingredient in desserts throughout Asia and also as a solid substrate to contain culture medium for microbiological work. Agar (agar-agar) can be also used as a laxative, a vegetarian gelatin substitute, a thickener for soups, in jellies, ice cream and other desserts, as a clarifying agent in brewing, and for paper sizing fabrics.