Bruh is a slang form of bro that became a deadpan reaction word in online meme culture, spreading through short video platforms such as Vine and later TikTok, Instagram Reels and YouTube Shorts. The single-word clip caught on because it could sum up disbelief, disappointment and secondhand embarrassment in less than a second, making it easy to drop into edits, gaming clips and reaction videos. It is now used alongside other reaction sounds like the shocked sound, and it remains popular because the flat delivery still reads clearly even without any context.