|a notional mark to one's credit earned for being seen to do the right thing|
|[C20: from the mistaken notion that Brownie Guides earn points for good deeds]|
Credit for a good deed, as in John earned a lot of brownie points for doing his boss's report for him. The term originated with the points earned for various achievements by the youngest group of the Girl Scouts, called Brownies. In the mid-1900s it was transferred to general use.