Coals

A black rock formed from prehistoric plant remains, composed largely of carbon and burned as a fuel.

"Put some coal on the fire."

A piece of coal used for burning (this use is less common in American English)

"Put some coals on the fire."

A type of coal, such as bituminous, anthracite, or lignite, and grades and varieties thereof.

A glowing or charred piece of coal, wood, or other solid fuel.

"Just as the camp-fire died down to just coals, with no flames to burn the marshmallows, someone dumped a whole load of wood on, so I gave up and went to bed."

To take on a supply of coal (usually of steam ships).

To supply with coal.

"to coal a steamer"

To be converted to charcoal.

To burn to charcoal; to char.