Picric acid is the chemical compound formally called 2,4,6-trinitrophenol (TNP). This yellow crystalline solid is one of the most acidic phenols and is vinylogous to nitric acid. Like other highly nitrated compounds such as TNT, picric acid is an explosive. Its name comes from Greek πικρος (pik' ros), meaning "bitter", reflecting its bitter taste. Its primary use, now outdated, is as an explosive. It has also been used in medicine (antiseptic, burn treatments), dyes, and as a chemistry agent.