noun
synthetic oil
Refers to oil produced artificially, often from coal or natural gas, as opposed to naturally occurring crude oil.
戦時中、日本は人造石油の生産に力を入れた。
During the war, Japan focused on producing synthetic oil.
石油 is natural crude oil, while 人造石油 is artificially manufactured.
Compound of 人造 (artificial, man-made) and 石油 (oil, petroleum).