There is nothing confusing about it if you're at least a little bit educated. If anything, they are the least confusing, Ant drops the ball at opus->fable. For OpenAI, it's:

Luna, means "moon", smallest.

Terra, means "earth", bigger than the moon.

Sol, means "sun", the biggest object in the solar system.

Astra, plural of the word "astrum" which means "star".

Anyone who gets confused should be embarrassed.