Why is ganymede called a moon and not a plamet

The discovery, along with three other Jovian moons, was the first time a moon was discovered orbiting a planet other than Earth. Galileo's discovery eventually led to the understanding that planets orbit the sun, instead of our solar system revolving around Earth. Galileo called this moon Jupiter III.

on the planet jupiter, the acceleration due to gravity is approximately 26 m s2 , roughly 2.7 times the acceleration due

the scientific method.