coal

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A natural dark brown to black graphitelike material used as a fuel, formed from fossilized plants and consisting of amorphous carbon with various organic and some inorganic compounds.
2. n. A piece of this substance.
3. n. A glowing or charred piece of solid fuel.
4. n. Charcoal.
5. v. To burn (a combustible solid) to a charcoal residue.
6. v. To provide with coal.
7. v. To take on coal.

Century Dictionary and Cyclopedia

1. n. A piece of wood or other combustible substance, either ignited or burning (a “live coal” or “glowing coal”), or burned out or charred (a “dead coal,” charcoal, cinder).
2. n. A solid and more or less distinctly stratified mineral, varying in color from dark-brown to black, brittle, combustible, and used as a fuel, not fusible without decomposition, and very insoluble. It is the result of the transformation of organic matter, and is distinguished by its fossil origin from charcoal (def. 1). which is obtained by the direct carbonization of wood. (See coal-plant.) Coal always contains more or less earthy matter, which is left behind in the form of ash after combustion. The quantity of the ash varies considerably, but in good coal does not usually exceed from 5 to 10 per cent. in weight. Coal can, however, be used for fuel, in default of a better material, when the amount of ash is much larger than this. Coal consists essentially of carbon, together with hydrogen, oxygen, and nitrogen; and sulphur is rarely if ever absent. The most general subdivision of coal is into hard and soft. The former is that coal which consists almost entirely of carbon; the latter is that in which there is a considerable percentage of hydrogen. Hard coal is generally called anthracite; bituminous coal, or simply coal, is the designation of the ordinary soft coal almost everywhere in general use where coal is burned, except in the eastern and Atlantic United States. In anthracite the bituminous or volatile matter constitutes usually less than 7 per cent. of the whole; in soft or bituminous coal it is usually more than 18 per cent. Coal intermediate in character between anthracite and bituminous coal is called semi-anthracite or semi-bituminous, according as it approaches anthracite or bituminous coal more nearly in character. The material driven off from coal on ignition is not really bitumen, for coal is insoluble, while bitumen is soluble. The name comes from the fact that bituminous coal behaves on being heated very much as bitumen itself does—that is, it swells up more or less, fuses together, and burns with a bright flame and considerable dense smoke. Coal occurs in all the geological formations, from the lowest in which land-plants have been found (the Devonian) up to the highest; but the coal of the great manufacturing countries, England, France, Germany, and the eastern United States, is nearly all of the same geological age, and is obtained from the formation called the Carboniferous. (See carboniferous.) The coal of Australia, India, and a part of that of China is of later geological age than the Carboniferous, being Mesozoic, and not Paleozoic. There is also a large quantity of good coal in various parts of the world in formations even more recent than the Mesozoic. In general, however, from the time of the Carboniferous on, the conditions were continually growing less favorable for the formation of coal on a large scale; so that each successive age has less coal to show, and that on an average of poorer quality than the coal of the true Carboniferous epoch. (See lignite.) Also called stone-coal, mineral coal, and formerly sea-coal. [Coal in this sense is used as a collective noun without a plural; but in Great Britain the plural form is also used in speaking of a quantity of coal, with reference to the pieces composing it: as, to lay in a supply of coals; put more coals on the fire.]
3. n. Same as slack.
4. To burn to coal or charcoal; make into coal; char.
5. To mark or delineate with charcoal.
6. To provide with coal; furnish a supply of coal to or for: as, to coal a steamship or a locomotive.
7. To take in coal for use as fuel: as, the vessel coaled at Portsmouth.
8. n. Coal which will not fuse together and cohere in masses when burned. It is desirable that coal should do this for forge fires in certain kinds of work.

Wiktionary

1. n. uncountable A black rock formed from prehistoric plant remains, composed largely of carbon and burned as a fuel.
2. n. countable A piece of coal used for burning. Note that in British English the first of the following examples would usually be used, whereas in American English the latter would.
3. n. countable A type of coal, such as bituminous, anthracite, or lignite, and grades and varieties thereof.
4. n. countable A smouldering piece of material.
5. v. To take on a supply of coal (usually of steam ships).
6. v. To be converted to charcoal.

GNU Webster's 1913

1. n. A thoroughly charred, and extinguished or still ignited, fragment from wood or other combustible substance; charcoal.
2. n. (Min.) A black, or brownish black, solid, combustible substance, dug from beds or veins in the earth to be used for fuel, and consisting, like charcoal, mainly of carbon, but more compact, and often affording, when heated, a large amount of volatile matter.
3. v. rare To burn to charcoal; to char.
4. v. To mark or delineate with charcoal.
5. v. To supply with coal.
6. v. To take in coal.

WordNet 3.0

1. v. take in coal
2. n. a hot fragment of wood or coal that is left from a fire and is glowing or smoldering
3. v. supply with coal
4. n. fossil fuel consisting of carbonized vegetable matter deposited in the Carboniferous period
5. v. burn to charcoal