The name for a really awesome and pretty girl who is one of the best friends you will ever have. She is up for any fun or random activity you can think of and never gets tired of it (or at least never shows it). She seems to radiate warmth and happiness and always has a smile on her face. Anna is that one-of-a-kind friend that everyone needs.
"Yeah, Anna and I are going ice-skating tonight, hiking tomorrow, and we're playing card games all day the day after that!"
"Wow, obviously Anna isn't much of a hiker, but every time I asked her if she needed a break, she just smiled and kept on going!"