I have to laugh.
True story -
Was in a rather large, familiar bike shop a few months back and noticed a new poster w/ a lot of writing on the walls (at eye level) in several spots - two in the tire section. It was a detailed poster showing (almost) all the tire sizes and the various nomenclatures for each. Only a couple of images for reference.
Upon checking out I said to the store-manager-looking-guy, "Thanks for trying to keep all us dumb customers clear about the tire sizes we need?" He replied, "Training tool for new employees!" He paused, then mumbled audibly, "and translation guide for the experienced ones." I could only chuckle and reply, "me too, thankfully tubulars are one diameter". Then he said, "We need a bigger one (chart) for wheels and all brake combos".