Legal Definitions - casus amissionis

Definition: Casus amissionis is a Latin term that means "the occasion of the loss." It refers to the circumstances under which a document is lost or destroyed.

In legal cases where the contents of a lost document need to be proven, the circumstances under which the document was lost are required evidence. For example, if a will is missing, the court may require evidence of how it was lost or destroyed.

Today, lost documents are covered by Federal Rule of Evidence 1004(1).