I know the sun is called Sol, and I'm pretty sure the moon is called Luna. Those may be the Latin words, but they nevertheless are considered to be the names. I've rarely heard these names used, though, except in science fiction.
When you block a person, they can no longer invite you to a private message or post to your profile wall. Replies and comments they make will be collapsed/hidden by default. Finally, you'll never receive email notifications about content they create or likes they designate for your content.
Note: if you proceed, you will no longer be following .