The hole located at the end of your rectum that secrets brown substances. Also known as your anus and can be used for anal sex.
"Let me see that Brownhole!"
by Geoff Schwab May 20, 2008
The result of a person (or organisation) disappearing so far up their own backside that they warp a hole in spacetime from which not even logic can escape.
I came perilously close to the event horizon of a brownhole today and frankly, I'm lucky not to be buried in a whole heap of super-dense shit.
by VliegendeSchot October 27, 2015