Pluto has five known moons. The largest and most well-known moon of Pluto is called Charon. Charon was discovered in 1978 by American astronomer James Christy.
Charon is an interesting moon because it is quite large in comparison to Pluto itself. In fact, Charon is so large that it is often referred to as a "moon-planet binary" system, meaning that Pluto and Charon orbit around a common center of gravity located between them. This relationship is unique among the moons in our solar system.
As for its name, Charon was named after the mythological ferryman who transported souls across the river Styx in Greek mythology. The name was chosen because the first four letters of Charon also happen to be the initials of James Christy, the astronomer who discovered the moon.
In addition to Charon, Pluto has four smaller moons named Nix, Hydra, Kerberos, and Styx. These moons were discovered using the Hubble Space Telescope and were officially named in 2013, following the New Horizons mission to Pluto.