A penny is a coin or a unit of currency in various countries. Borrowed from the Carolingian denarius, it is usually the smallest denomination within a currency system. Presently, it is the formal name of the British penny (abbr. p) and the de facto name of the American one-cent coin (abbr. ¢) as well as the informal Irish designation of the 1 cent euro coin (abbr. c). Due to inflation, pennies have lost virtually all their purchasing power and are often viewed as an expensive burden to merchants, banks, government mints and the public in general.