English
retroactivity
From retroactive + -ity.
A compound of retroactive + -ity
Proto-Indo-European *h₂eǵ- ‘to drive’
…
Latin āctīvus ‘active’
Old French actif ‘active’
French actif ‘active’
French rétroactif
English retroactive
Today it means
noun The state or characteristic of being retroactive.
Language periods are conventional ranges, not dates for this word.
Etymograph / retroactivity