British Dictionary definitions for heap coals of fire on someone's head
a combustible compact black or dark-brown carbonaceous rock formed from compaction of layers of partially decomposed vegetation: a fuel and a source of coke, coal gas, and coal tarSee also anthracite, bituminous coal, lignite, peat 1
Word Origin and History for heap coals of fire on someone's head
Old English col "charcoal, live coal," from Proto-Germanic *kula(n) (cf. Old Frisian kole, Middle Dutch cole, Dutch kool, Old High German chol, German Kohle, Old Norse kol), from PIE root *g(e)u-lo- "live coal" (cf. Irish gual "coal").
Meaning "mineral consisting of fossilized carbon" is from mid-13c. First mentioned (370 B.C.E.) by Theophrastus in his treatise "On Stones" under the name lithos anthrakos (see anthrax). Traditionally good luck, coal was given as a New Year's gift in England, said to guarantee a warm hearth for the coming year. The phrase drag (or rake) over the coals was a reference to the treatment meted out to heretics by Christians. To carry coals "do dirty work," also "submit to insult" is from 1520s. To carry coals to Newcastle (c.1600) Anglicizes Greek glauk eis Athenas "owls to Athens."
A dark-brown to black solid substance formed from the compaction and hardening of fossilized plant parts in the presence of water and in the absence of air. Carbonaceous material accounts for more than 50 percent of coal's weight and more than 70 percent of its volume. Coal is widely used as a fuel, and its combustion products are used as raw material for a variety of products including cement, asphalt, wallboard and plastics. See more at anthracitebituminous coallignite.