煤 (méi) is the Chinese word for "coal," a black or brownish-black sedimentary rock that is primarily composed of carbon. It is formed from the remains of ancient plants that have been subjected to heat and pressure over millions of years. Coal is a significant source of energy and is widely used for electricity generation and industrial processes. In addition to its energy applications, coal is also used in the production of coke, which is essential for making steel. However, the burning of coal releases greenhouse gases, contributing to climate change, leading to a global shift towards cleaner energy sources.