Ethene and Trichloroethane

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

Trichloroethane and ethene are semantically related. In some cases you can replace term "Trichloroethane" with "Ethene", this nouns are similar.

Trichloroethane noun - A heavy colorless highly toxic liquid used as a solvent to clean electronic components and for dry cleaning and as a fumigant; causes cancer and liver and lung damage.

Ethene and trichloroethane are semantically related. You can use "Ethene" instead a noun "Trichloroethane".