A signet is an official SEAL or stamp used to authenticate documents, and it can come in several forms. The most common form is a SEAL, which is a four-letter word. A SIGIL is a five-letter word that is a sign or symbol used to represent a person, family, or institution. Finally, a sealring is an eight-letter word that is a ring with a signet on it, usually worn by royalty or other high-ranking officials.