English
dichloro
From di- + chloro-.
Proto-Indo-European *ǵʰelh₃- ‘green, yellow’
Proto-Indo-European *ǵʰl̥h₃rós
Proto-Hellenic *kʰlōrós ‘greenish-yellow, pale green’
Ancient Greek χλωρός ‘pale green’
English chloro-
Today it means
noun Two chlorine atoms in a molecule.
Language periods are conventional ranges, not dates for this word.
Etymograph / dichloro