Fernet is a bitter, aromatic spirit made from a blend of herbs, roots, and spices. It is a popular digestif in many countries, especially in Argentina, where it is often mixed with coke and served as a cocktail. There are several synonyms for fernet, including bitter liqueur, herbal digestif, amaro, and tonic. Bitter liqueur is a generic term used to describe any spirit that has a bitter taste, while herbal digestif refers to any drink that is consumed after a meal to aid digestion. Amaro is a term used specifically for Italian bitter liqueurs, while tonic refers to any alcohol with a bitter taste that is consumed to aid in digestion.