A cordial is any invigorating and stimulating preparation such as a peppermint cordial. The term derives from obsolete medical usage, as various beverages were concocted which were believed to be beneficial to one's health, especially for the heart (cordialis in Latin).
In the United Kingdom and Australia, cordial is an extremely sweet (usually entirely artificial) non-alcoholic drink concentrate that is mixed with water to taste. This cordial is said to have some medical properties for stomach problems.
Recipes: Cordials and Liqueurs