Ethylene and Olefin

Ethylene noun - A flammable colorless gaseous alkene; obtained from petroleum and natural gas and used in manufacturing many other chemicals; sometimes used as an anesthetic.

Olefin and ethylene are semantically related. In some cases you can use "Olefin" instead a noun "Ethylene".

Olefin noun - Any unsaturated aliphatic hydrocarbon.

Ethylene and olefin are semantically related. Sometimes you can replace term "Ethylene" with "Olefin", this nouns are similar.