A milkshake is a popular concoction made using milk, ice cream, and other flavors such as syrup and whipped cream. Malt is a particular type of shake that contains malted powder. A milkshake is a type of shake that uses malt powder as an ingredient. Malt powder is barley and wheat powder that is intended to give strength to small children and older adults who are lacking in nutrition.
The flavor of malt does not match with many fruit syrups, but you can use any fruit flavor to make a shake. Malt contains either malt powder or syrup. Malt is just a typical shake, but not all shakes are malts.