bratan Share definition Flag Russian slang word derived from the word 'brat' meaning brother. This is something you would call a close male friend or family member.Pronounced brAh-tahn. Russian: Spasibo, bratan. English: Thanks, brother. bratan by Polkovnik February 18, 2012 0 0 Get merch Get the bratan mug. Buy Now — $32.95 See more merch