What is what does retroactive mean?

Retroactive refers to something that applies to events or actions that have taken place in the past. It means that an action or decision is applied to situations or circumstances that happened before the action or decision was made, rather than only applying to the present or future. This can apply to laws, taxes, contracts, policies, and other types of regulations or actions. The purpose of retroactive measures is often to correct an error or oversight, provide relief or compensation, or change the outcome of a previous action or decision.