"capable of burning," 1520s, from French combustible, or directly from Late Latin combustibilis, from Latin combustus, past participle of combuere "to burn up, consume" (see combustion). Figurative sense "easily excited" is from 1640s. As a noun, "a substance that will burn," from 1680s. Related: Combustibility (late 15c.).
"pile or heap of wood or other combustible materials for burning a dead body," 1650s, from Latin pyra and directly from Greek pyra (Ionic pyrē) "funeral pyre; altar for sacrifice; watch-fire; hearth; any place where fire is kindled," from pyr "fire" (from PIE root *paewr- "fire," source also of fire (n.)). Related: Pyral.
also pin-wheel, 1690s, "a wheel in the striking train of a clock in which pins are fixed to lift the hammer," from pin (n.) + wheel (n.). The fireworks sense of "long paper case filled with a combustible composition and wound spirally about a disk so that, when supported vertically and lit, it revolves in a wheel of fire" is from 1869.
c. 1400, "capable of burning or destroying organic tissue, corrosive," from Latin causticus "burning, caustic," from Greek kaustikos "capable of burning; corrosive," from kaustos "combustible; burnt," verbal adjective from kaiein, the Greek word for "to burn" (transitive and intransitive) in all periods, which is of uncertain origin with no certain cognates outside Greek.
Figurative sense of "sarcastic, severely critical" is attested from 1771. As a noun "a caustic substance," early 15c., from the adjective.
1730, hypothetical inflammatory principle, formerly believed to exist in all combustible matter, from Modern Latin (1702), from Greek phlogiston (1610s in this sense), neuter of phlogistos "burnt up, inflammable," from phlogizein "to set on fire, burn," from phlox (genitive phlogos) "flame, blaze" (from PIE root *bhel- (1) "to shine, flash, burn"). The theory was propounded by Stahl (1702), denied by Lavoisier (1775), defended by Priestley, but generally abandoned by 1800. Related: Phlogistic; phlogisticated.
Old English col "charcoal; live coal, piece of wood or other combustible substance, either burning or having been burned," from Proto-Germanic *kula(n) (source also of 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" (source also of Irish gual "coal").
Meaning "solid mineral consisting of fossilized carbon, combustible and used as fuel," is from mid-13c. The thing itself is 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 "add to that of which there is already an abundance, do unnecessary labor " (c. 1600) is a local variant on an ancient class of expression: Latin had in litus harenas fundere "pour sand on the beach," in silvam ligna ferre "carry wood to the woods;" Greek glauk eis Athenas "owls to Athens." Newcastle is in the midst of a great coal-producing region. The ancient view is not necessarily the modern one. A historian, noting that the medieval English exported manufactured cloth to the Low Countries, where weaving was a major industry, writes, "it is always sensible to send coals to Newcastle or owls to Athens if you can be sure of underselling the locals" [George D. Painter, "William Caxton," 1976]