Coal mining is the process of extracting coal from the ground.

Coal liquefaction is a process of converting coal into liquid hydrocarbons: liquid fuels and petrochemicals.

Coal gasification is the process of producing syngas—a mixture consisting primarily of carbon monoxide (CO), hydrogen (H2), carbon dioxide (CO2), natural gas (CH4), and water vapour (H2O)—from coal and water, air and/or oxygen.

A flammable gaseous fuel made from coal and supplied to the user via a piped distribution system. It is produced when coal is heated strongly in the absence of air.

Coal forests were the vast swathes of wetlands that covered much of the Earth's tropical land areas during the late Carboniferous (Pennsylvanian) and Permian times.

Coal dust is a fine powdered form of coal, which is created by the crushing, grinding, or pulverizing of coal.

Coal combustion products (CCPs), also called coal combustion wastes (CCWs) or coal combustion residuals (CCRs) are categorized in four groups, each based on physical and chemical forms derived from coal combustion methods and emission controls.

Coal bed natural gas is found in underground coal layers.

Coalbed methane extraction is a method for extracting methane from a coal deposit.

Coal analysis techniques are specific analytical methods designed to measure the particular physical and chemical properties of coals.

Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams.

Similar to the counter-current type, but the gasification agent gas flows in co-current configuration with the fuel.

In liquids, the cloud point is the temperature below which a transparent solution undergoes either a liquid-liquid phase separation to form an emulsion or a liquid-solid phase transition to form either a stable sol or a suspension that settles a precipitate.

In a closed-loop control system, the control action from the controller is dependent on the desired and actual process variable.

A closed system, being enclosed by selective walls through which energy can pass as heat or work, but not matter.

A cooling system that does not rely on a constant supply of cooling medium to operate. Closed loop systems have a fixed volume of fluid that requires none or infrequent topping up to maintain its cooling efficiency.

The nuclear fuel cycle is referred to as an open fuel cycle if spent fuel is reprocessed.

Clipping is a form of distortion that limits a signal once it exceeds a threshold.

Climate sensitivity is a measure of how much the Earth's climate will cool or warm after a change in the climate system.

The term stranded assets has gained significant prominence in environmental and climate change discourse, where the focus has been on how environment-related factors (such as climate change policy) could strand assets in different sectors.