i think you're referring to the original playstation. the above infor are correctm indeed. but they forgot to mention that PSX is ALSO a nickname for the Original Playstation.
PSX is also a popular nickname for the original PlayStation video games console. The "X" appears because Sony originally developed the PlayStation as a CD-ROM and SNES hybrid unit. When the project was halted by Nintendo, Sony decided to redesign the PlayStation as a stand alone console, which was known internally as the PlayStation Experimental.