x-ray : ex- ray
adjective
    1 because there isn't a great deal in the "x" category : whisky, x-ray, yankee, zebra. Mars bar, tango, yorkie (we've already had that one) errrm.. Apple. Banana... errrm..

xenon : zen on
noun
    1 an inert gas : parp
    2 also a cracking shoot-em-up for the amiga : /geek

xenon II: megablast : zen-on too meg-a-blaaa-st
noun
    1 Another cracking game, by the Bitmap Brothers, with title music by Bomb The Bass. : Xenon II:megablast is the sequel to Xenon

xenophobe : zeenophobe
noun
    1 someone who doesn't like a particular warrior princess : That Lucy Lawless is a right ugly munter - I must be a xenophobe

xerox : z-air-ro-cks
noun
    1 The document company : I'm just gonna go and xerox my arse

xylophone : zy-lo-fone
noun
    1 plinky plonk : lawks! I can see her xylophone
    2 Instrument Patrick Moore plays : Patrick Moore plays the Xylophone , Pa Pa Pa Pa Pa Patrick
    3 A word that fits into the X category : *Pling!*