The first thing I thought of when I thought brave was that Sarah Bareilles song "Brave"
"Say what you wanna say
And let the words fall out
Honestly, I wanna see you be brave"
Which is about speaking out and standing up for what you think is right instead of remaining silent and passive. I think this sentiment applies to far more than words, though. It's about not lying down and taking it, even when it would be easier to remain silent, inactive, and let something consume you. Being brave is about gathering the willpower to move life in the direction you want it to go, regardless of whatever forces are working against you. Fighting as hard as you can for what you want.