Terra

The name "Terra" is an improoved name for the planet that is currently called "Earth".
The problem with the name "Earth" is that there is also the common mass-noun "earth",
which is a synonym for the word "soil".
Also, the name "Terra" is a roman deity-name, like that of the other planets in this
star-system, whereas the name "Earth" is a derivative of the common-noun "earth".