Exam revision for a culinary student looks like this...

4 different cuts here - medium dice, brunoise, julienne, batonnet

This is CMI-Julienne. CMI as you know is teenage lingo for cannot-make-it!
A julienne is supposedly 3mm x 3mm x 5cm

CMI medium dice 12mm cube

Brunoise, pronounced "broon-wahz" (In French, pronounce the s if it is
followed by an e, as I've been told), is a 3mm cube.

And the reason why we need to do this? Well, for one, it's not called culinary arts for nothing. Food cook more evenly when it's cut to same measurement and fashion and affects taste for the discerning tongue. It is also supposedly more visually appealing thus further whetting the diner's appetite.