"Charcoal color" refers to a dark gray or black color, similar to the color of charcoal, which is a carbon-rich substance often used for drawing or grilling. Full definition
The crib and furniture are stained with a dark charcoal color that goes well with tons of different color options for the surrounding room. (allamericanreviews.com)
My son likes the deep charcoal color and the fact that it is a solid color. (menswearhouse.com)
The rich charcoal color is accented with black leather trim, including a convenient handle. (potterybarn.com)