Arrowroot, or arrowroot starch is ...

Arrowroot, or arrowroot starch, is a powdery product made from the arrowroot plant, a starchy tropical root. The plant is dried and ground up to make the powder n is used as a thickener in the kitchen, much like cornstarch. Much like cornstarch, it is an excellent thickening agent. It has about twice the thickening power of regular flour. Arrowroot is used in recipes as it is extremely digestible.
Arrowroot is useful as a thickening agent for soups and sauces.
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Never mix arrowroot with dairy products, as it can produce an unpleasant texture. 
Arrowroot is a powdery, highly digestible starch that is commonly used in cooking throughout the Caribbean. 
Arrowroot starch also makes an excellent substitute for talcum powder in cosmetics and it was once used in the paper making industry.
Arrowroot is gluten free so it’s an excellent substitute for cornstarch and flour as a thickening agent in sauces, gravies, pie fillings, and puddings. 
The starch also freezes well and dissolves well at lower temperatures. 
A mixture of cornstarch and liquid (usually water or stock) used to thicken a sauce or soup is called a Slurry.
Roux pronounced "roo" is one of the basic thickening agents in the culinary arts. Used primarily for thickening sauces and soups, roux is made from equal parts fat and flour, and the "equal parts" are measured by weight, not volume.
Liaison in the culinary arts means a mixture of egg yolks and heavy cream that is used to thicken a sauce.
Chinese Potato is the lesser known but healthier cousin of the potato.