Seal of the United States
The official die or signet, which has a raised emblem and is used by federal officials on documents of importance.
The United States seal is sometimes officially known as the great seal. The SECRETARY OF STATE has custody and charge of the official seal and makes out, records, and affixes the seal to all civil commissions for officers of the United States, who are appointed by the president alone, or by the president with the advice and consent of the Senate. In order for the seal to be affixed to any commission or other instrument, the president must sign or specially warrant the commission. When the seal is affixed to an appointment, such appointment is made and the commission is valid.
Each state also has an official seal, which is carefully described by law and serves functions on the state level of government that are similar to those of the seal of the United States on the federal level.