Charon (Hebrew: כארון, Greek: Χάρων) is the largest of the five known natural satellites of the dwarf planet Pluto. It has a mean radius of 606 km (377 mi). At half the diameter of Pluto, it is the largest known satellite relative to its parent body. Charon is so massive that the barycenter of the Pluto–Charon system lies outside of Pluto, which is unusual in the solar system. Charon's orbit around Pluto takes about 6.4 Earth days, and one rotation of Charon on its axis takes the same amount of time. This is known as a tidal locking or being in synchronous rotation, meaning that the same face of Charon always points toward Pluto. In French, Charon is known as "Charon," in German as "Charon," in Spanish as "Carón," and in Japanese as "カロン" (Karon).