What is the meaning of Coal?

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

A type of coal, such as bituminous, anthracite, or lignite, and grades and varieties thereof, as a fuel commodity ready to buy and burn.

A piece of coal used for burning

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

charcoal.

Content of low quality.

 Bombs emitting black smoke on impact.

Failing to be humorous or of extremely poor quality.

Black like coal; coal-black.

To post low-quality content online.

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

To supply with coal.

To be converted to charcoal.

To burn to charcoal; to char.

To mark or delineate with charcoal.

Source: wiktionary.org