a hard, black substance similar to coal that can be used as fuel or, in the form of sticks, as something to draw with

charcoal for the barbecue 烧烤用的木炭

I prefer sketching in charcoal to pencil. 比起铅笔来，我更愿用炭笔画素描。

a charcoal drawing 炭笔画

The uniform is charcoal (grey) (= dark grey) and red. 制服是深灰色配红色的。