Definition from Wiktionary, the free dictionary
Alternative forms 
Comes from the points Girl Guides or Girl Scouts at the Brownie level (ages 6-8) receive for doing specific tasks that when accumulated earn them badges (a sign of recognition) to wear on their Brownie Uniform.
- (idiomatic, slang, chiefly plural) Credit or praise for good work or a good deed, often for the express purpose of currying favor.
- You're really going to get some brownie points from the teacher for that fantastic essay!