fossil fuel

Từ điển Oxford Advanced Learner 8th

ˈfossil fuel [fossil fuel] BrE NAmE noun countable, uncountable
fuel such as coal or oil, that was formed over millions of years from the remains of animals or plants
•Carbon dioxide is produced in huge amounts when fossil fuels are burned.
compare ↑biomass

Example Bank:
•Fossil fuel reserves are rapidly being depleted.
•Gas is the only fossil fuel without environmental problems.