xor

Conjunction meaning either the thing preceding it or the thing following it, but not both.

I'll order a pizza xor Chinese.

Xenu

$cientologists' version of god, he made his prisoners watch movies, sort of an intergalactic MST3K, which are now the world's religions. Then he nuked the world 95,000,000 years ago. (Source: Operating Thetan-III, the part of their religion $cientologists don't want you to read.)

XXX

Porno, pr0n, peep shows...You get the idea.

An etymological note: An "X" rating used to mean a film wasn't rated. (In fact, one X-rated movie, Midnight Cowboy, won an Oscar.) Pornographers got hold of the X in the 70s, and soon the X became associated with ill-repute. XXX is just a way of advertising it.

I'm probably the last user on the planet who hasn't seen Pam and Tommy's XXX video.

web site

Address on the web, such as www.foo.com