In the law, a seal affixed to a contract or other legal instrument has had special legal significance at various times in the jurisdictions that recognise it. In the courts of common law jurisdictions, a contract which was sealed ("made under seal") was treated differently from other written contracts (which were "made under hand"), although this practice gradually fell out of favour in most of these jurisdictions in the 19th and early 20th century. The legal term seal arises from the wax seal used throughout history for authentication (among other purposes).
Originally, only a wax seal was accepted as a seal by the courts, but by the 19th century many jurisdictions had relaxed the definition to include an impression in the paper on which the instrument was printed, an embossed paper wafer affixed to an instrument, a scroll made with a pen, or the printed words "Seal" or "L.S." (standing for the Latin term locus sigilli meaning "place of the seal").
Notwithstanding their reduced significance, seals are still used on contracts, usually in the impression on paper form.