Any material, solid, liquid or gaseous, that can be ignited easily and will burn rapidly under normal environmental conditions. Combustion usually requires a heat source and oxygen, but some materials may ignite spontaneously at room temperature. Historically, flammable and inflammable have always meant the same thing. Currently, the trend is to only use 'flammable' since it is grammatically correct and less likely to be misconstrued. Nonflammable is the opposite of flammable.
Synonyms and Related Terms
inflammable material; flammability; inflammability