combustible

a. 易燃的,燃烧性的,易动激情的
n. 燃质物,可燃物

Petrol is (highly) combustible.

汽油（极）易燃.

A hypothetical substance formerly thought to be a volatile constituent of all combustible substances released as flame in combustion.

燃素，热素原来假设的在所有燃烧物质中挥发性的一种物质成分，在燃烧中作为火焰而被释放出来