Turning a block of wood translucent? What is it called?

Back in 7th grade, I remember a classmate in my "workshop" class turning a block of wood translucent by using some sort of machine. After it was done, the wood had no color, just translucent and not very clear though. So what is this called? I tried googling translucent wood and i can't find what I'm looking for. Does anybody know what this is called?