An acronymn used to mean Sony PlayStation as in the games console.

Why the 'X'? OK, here's a bit of history. In 1988 Nintendo was courting with Sony to make a CD-ROM add on, utilising the CD-ROM/XA format, for its upcoming Super Nintendo / Super Famicom. Under the deal, Nintendo would sell an add on drive, while Sony would make a combined Super Famicom and CD-ROM drive. The combined device would be known as the PlayStation. As part of the deal, Sony wanted exclusive rights to the licencing of the SFC CD-ROM format, and Nintendo wasn't too keen on the idea. After a bit of backtracking, and Nintendo talking to Philips behind Sony's back, the drive was eventually cancelled, and with it, the original PlayStation. The head of Sony was, understandably, quite pissed off. Instead of closing the project outright, he instructed the team who had been working on the system to develop a new machine to get back at Nintendo, and establish Sony's position in the video games market. The new system was codenamed the "PlayStation X" or PSX. Since early previews in magazines used the PSX moniker, it tended to stick.

Incidentally, the PS2 was on occasion refered to as the PSY. I'm guessing that this was another internal codename. That one didn't stick.

Yeah yeah, this is redundant to meaning of psx, but this is a more sensible place to put it. FWIW tho, I'm not a fan of either console. I have a PSX, but it is seldom used. Source: Edge 17