mass noun
1- a solid fuel made by heating coal in the absence of air so that the volatile components are driven off焦炭。
1.1
- carbon residue left after the incomplete combustion of petrol or other fuels（汽油或其他燃料不完全燃烧后所剩的）废气渣。
词源
late Middle English （in the sense 'charcoal'）： of unknown origin. The current sense dates from the mid 17th cent.