Tip of the penis.
Can also be used as an insult.
Only Britain has been blessed with this amazing word so far, but the Gods are trying to find a way to spread it around the entire world.
Random: I dress up as death and point at old people as they leave the bingo centre.
Me: You bellend.
('bel-end, noun) A derogatory term used sub-frequently in British culture, derived from Bell End, meaning the tip of a penis, and a usual saying of British internetstar, Devvo, of Fat-pie.com
This type of person is an absolute twat who never fails to annoy you. They are loud and not well educated and often blurt out inappropriate comments resembling an arsehole, or in this case, a total bellend.
That newlad at work is a boisterous bellend and really pisses me off