English

exomethylene

From exo- + methylene.

Proto-Indo-European *h₁eǵʰs ‘out of’

Proto-Hellenic *eks

Ancient Greek ἐκ ‘Out of, from’

Ancient Greek ἔξω ‘outer’

English exo-

French méthylène

Today it means

noun A methylene group attached by a double bond to the outside of a ring

Language periods are conventional ranges, not dates for this word.

Etymograph / exomethylene