a. Inflammable. [ Obs. ] Shak. [ 1913 Webster ]

n. [ L. combustio: cf. F. combustion. ] 1. The state of burning. [ 1913 Webster ]

2. (Chem.) The combination of a combustible with a supporter of combustion, producing heat, and sometimes both light and heat. [ 1913 Webster ]

Combustion results in common cases from the mutual chemical action and reaction of the combustible and the oxygen of the atmosphere, whereby a new compound is formed. Ure. [ 1913 Webster ]

Supporter of combustion (Chem.), a gas, as oxygen, the combination of which with a combustible, as coal, constitutes combustion. [ 1913 Webster ]

3. Violent agitation; confusion; tumult. [ Obs. ] [ 1913 Webster ]

There [ were ] great combustions and divisions among the heads of the university. Mede. [ 1913 Webster ]

But say from whence this new combustion springs. Dryden. [ 1913 Webster ]

. (Mech.) (a) A space over, or in front of, a boiler furnace where the gases from the fire become more thoroughly mixed and burnt. (b) The clearance space in the cylinder of an internal combustion engine where the charge is compressed and ignited. [ Webster 1913 Suppl. ]