cornstarch

n. starch made from corn (used as a thickening agent)

Cornstarch, or cornflour, is the starch of the maize grain, commonly known as corn. It is also ground from the endosperm, or white heart, of the corn kernel. It has a distinctive appearance and feel when mixed raw with water or milk, giving easily to gentle pressure but resisting sudden pressure (see Non-Newtonian fluid). It is usually included as an anti-caking agent in powdered sugar (10X or confectioner's sugar). For this reason, recipes calling for powdered sugar often call for at least light cooking to remove the raw cornstarch taste.
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Noun
1. starch prepared from the grains of corn; used in cooking as a thickener
(synonym) cornflour
(hypernym) starch, amylum

(n.)
Starch made from Indian corn, esp. a fine white flour used for puddings, etc.
  

A white, powdery thickener finer than flour. It is extracted from the starch endosperm of wheat or corn. It must be dissolved in a cold liquid before it is added to a hot mixture or it will lump. It results in a glazy, opaque finish.