X date – behave better next time
A direct mail term referring to the date a particular offer will terminate.

Xlapse – make for a bruised cheek
A measure of the number of people denied access to the Internet. It is usually calculated by the number denied access multiplied by the number of hours access was denied. Usually applied for devastating web failure with widespread effect.

XML – where all the Hempsteads came from
What in full is referred to by programmers as eXtensible Markup Language. It allows the interchange of structured data. Okay, I'll come clean: I was just a little bit stuck for an 'X'. Forgive me.

Z fold – neat slumbering
A fold in printed material resembling the letter Z that allows the paper to be presented as three equal parts. Also known as a zigzag fold.