Restitutio ad integrum, or restitutio in integrum, is a Latin term that means "restoration to original condition". It is one of the primary guiding principles behind the awarding of damages in common law negligence claims.
In European patent law, it also refers to a means of redress available to an applicant or patentee who has failed to meet a time limit despite exercising all due care.
In ancient Roman law, it was a specific method of praetor intervention in an otherwise-valid legal action that was viewed as especially unjust or harmful.