Fossil fuel and Naphtha

Fossil fuel noun - Fuel consisting of the remains of organisms preserved in rocks in the earth's crust with high carbon and hydrogen content.

Naphtha and fossil fuel are semantically related In some cases you can use "Naphtha" instead a noun phrase "Fossil fuel".

Naphtha noun - Any of various volatile flammable liquid hydrocarbon mixtures; used chiefly as solvents.

Fossil fuel and naphtha are semantically related in oil topic. You can use "Fossil fuel" instead a noun "Naphtha".