rehydrogenation

Etymology tree
Proto-Italic *wre-
Latin re-der.
Old French re-bor.
Middle English re-
English re-
Proto-Indo-European *wed-
Proto-Indo-European *-r̥
Proto-Indo-European *wódr̥
Proto-Hellenic *údōr
Ancient Greek ῡ̆̔́δωρ (hū̆́dōr)
Ancient Greek ὑδρο- (hudro-)lbor.
French hydro-
Proto-Indo-European *ǵenh₁-
Proto-Indo-European *-os
Proto-Indo-European *ǵénh₁os
Proto-Hellenic *génos
Ancient Greek γένος (génos)
Proto-Indo-European *-os
Proto-Indo-European *-ēs
Ancient Greek -ης (-ēs)
Ancient Greek -γενής (-genḗs)lbor.
French -gène
French hydrogènebor.
English hydrogen
Proto-Indo-European *-tis
Proto-Indo-European *-Hō
Proto-Indo-European *-tiHō
Proto-Italic *-tiō
Latin -tiō
Latin -ātiōlbor.
Old French -ationbor.
Middle English -acioun
English -ation
English hydrogenation
English rehydrogenation
From re- + hydrogenation.