Definition - What does Interlineation mean?
Interlineation is writing that occurs between the lines of a document. In the real-world practice of law and business, interlineation often happens when parties are reviewing a contract, decide to edit or add writing to a printed document without reprinting it, and then sign the document, making it official.
Justipedia explains Interlineation
Interlineation becomes an issue when courts are trying to decipher the original meaning of a document. The problem with interlineation is that it is difficult to ascertain that handwritten words on a document were added with the knowledge and consent of all the parties involved with the document. For this reason, most courts are reluctant to attach meaning to interlineation unless all parties have added their initials and a date next to the interlineated writing.