There's a five year old thread answering this, but instead of linking to it, i'll elaborate a little more on it. The j is easy, it stands for Java. And PCT...well, back in the good old DOS-days, i started writing 3d stuff on the PC. I started with some engine that was somewhere between Wolfenstein 3D and Doom. It had texture mapped walls, floors and ceilings and was capable of doing simple fogging and lighting effects. It was called Textmap for texture mapping. Back in these days, the next big thing for everybody was texture mapping of arbitrary surfaces, not just walls and floors. The easy but ugly approach was affine texture mapping, the better one was perspective correct texture mapping. I wrote an engine doing this and called it (P)erspective (C)orrect (T)exturemapping -> PCT. Later, i wrote a simple texture mapper in Java and called it jPCT, because adding a "j" for Java was very popular back then. That thing was the base from which jPCT as an engine evolved (some of this old code is still in jPCT even today) and simply kept the name.