What 'B' means in pencils?

"B" and "H" stand for "Black" (something that's debated, it can't be determined whether that's correct or not) and "Hard." B pencils have softer lead and H pencils have harder lead. The common pencil is a 2H (it'll say so right at the top of your Ticonderoga). There are different degrees of both, and the higher the number the harder or softer the lead; e.g. a 2B is a soft pencil and a 9B (which I believe is the highest) is the softest pencil. Same goes for H pencils. So if you're drawing and you need a shade that's really dark or close to black, you'll use a 6B, 8B, or 9B. If you need a shade that's really light, close to white, then you'll use a high numbered H pencil, like a 5H

different hardnesses and softnesses of the led..

Black

http://www.pencils.com/blog/hb-graphite-grading-sc...