2. A cordial is any invigorating and stimulating preparation; e.g., peppermint cordial. The term derives from obsolete medicinal usage, as various beverages were concocted which were believed to be beneficial to one's health, especially for the heart (cordialis in Latin).
From the Renaissance onwards, cordials were usually based on alcohol in which certain herbs, spices or other ingredients were allowed to steep. Examples of such cordials include:
Rosa Solis or Rosolio, derived from the carnivorous sundew plant; it was believed to not only invigorate the heart, but to be an aphrodisiac as well.
Royal Usquebaugh (from a Celtic word meaning life-water, which also gave rise to the word whiskey), a spicy concoction containing flecks of gold leaf thought to capture the sun's golden radiance.
Precious ingredients like gold, pearls and coral were sometimes added. These were believed to revive the spirit and to preclude disease.
Cordials became more and more frequently consumed recreationally as time progressed, eventually evolving into liqueurs.
In the UK cordials are often added to a measure of alcohol to make a "Rum and Black" (Rum with blackcurrant cordial added), "Rum and Pep" (Rum and peppermint cordial), Gin and orange, Vodka and lime, etc.
3. A very sweet, fruit-flavored drink made by adding cordial syrup to water. Sweeter than Kool-Aid, red cordial especially has a reputation for creating a "sugar high"