retroactivity

plural retroactivities

1. uncountableusuallyThe state or characteristic of being retroactive.
2. uncountableusuallylawThe application of a law to events that took place before it was made.

   Should the legislation pass with the retroactivity provision, the firm's percentage would apply to the amount already due the states; if not, it would apply to the amount they collect over the next 12 years.

   1994 May 6, Todd Purdum, “New Yorkers in Congress at War With a Lawyer”, in The New York Times, archived from the original on 03 Feb 2023

   1 more example

   it must be pointed out that the distinction between retroactivity and retrospectivity, while describing a real difference in the verbal form in which retrospective law is expressed, lacks normative and practical significance.

   2008, Ben Juratowitch, Retroactivity and the Common Law, page 12