Now, Yoko's name can either mean one of those examples, or Gainax could have just thought of the name and simply ran with it.
A friend of mine likes the term "sun child" for Yoko, and I agree. He told me:
With that I mind, he and I also happen to believe that Yoko herself was born on the surface and raised in her home village.
Sun Child fits Yoko's personality, too: She was always approachable, compassionate, generous, gregarious, mature and wise. Plus, she radiated such beauty!
That's all I got for now. What do you think?