Liaison

In cooking, a liaison is a thickening agent for soups, sauces and other mixtures. Beurre Manie, Roux, egg yolks or starches such as Flour, Cornstarch and arrowroot are among those agents used for thickening. A liaison is sometimes also referred to as a binder. Egg yolks, butter, flour, and puréed vegetables are all liaisons.