agar [ah-gahr, ag-er] noun
Also called agar-agar. A natural, gelatinous compound popular in Asian cuisines. It is derived from red algae (a seaweed) and often used as a vegetarian thickener in cooking and baking. This ingredient also has emulsifying properties, is tasteless and is most often used to make jellies, puddings and ice creams. It is sold in thin strips, flakes or in powdered form in Asian specialty stores or many Whole Foods stores.
Agar sets at room temperature and also holds its shape when heated, unlike gelatin, which needs to be chilled to set and will melt when heated. All of these properties make it very versatile. It is popular with molecular gastronomists.