A cordial is any invigorating and stimulating preparation that is intended for a medicinal purpose. The term derives from an obsolete usage. Various concoctions were formerly created that were believed to be beneficial to ones health, especially for the heart (cor' in Latin).
Some cordials, with their flecks of gold leaf and bright yellow hue, took their name from the "cordial virtues" of the rays of the sun, which some alchemists thought they contained.