1) What is MDF?
Medium density fibreboard.
I always thought MDF was an 'Americanism'...
Now I'm wondering what you guys call it, because I'm sure you must have it

It's a ubiquitous synthetic board used for carpentry and throughout the building industry for all sorts of things. Comes in various weights. Pale brown in colour. Very rigid. Doesn't warp. Easy to cut and work. Just don't breathe in the dust or you die young...