Jantawan
Jantawan in Thai means "skin like the moon" when a baby she is pure white but when she grows, her skin darkens. Usually she is a tomboy and acts like a boy, childish in her child hood but mysteriously beautiful once in her teens.

Jana-- and abbreviation of Jantawan
Girl 1: Did you see Jantawan?

Girl 2: Yes! She changed during the summer, all of that tomboy look is gone. Now look at her!
Girl 1: She is the prettiest girl around here now.