**The fourth root of 16 is 2.** In mathematics, the fourth root of a number is a number r that yields z when raised to power 4, where 4 is the degree of the root.

Roots are usually written in mathematics using the radical symbol. Any expression that contains a radical is referred to as a radical expression. Roots are important in various theories, particularly the theory of infinite series. The origin of roots is mostly speculative, but it is believed Arabic mathematicians started to use it as early as the 13th century. The square root is the most common root operation.