Skeleton keys are a type of key that can open multiple locks, regardless of their size or shape. They have been used for centuries and have become synonymous with ease of access and universal entry. Other terms used to describe skeleton keys include master keys, passkeys, or universal keys. While these terms all refer to the same kind of key, they may vary in their specific usage. For example, master keys may refer to a key that unlocks all the locks in a building, while a passkey may refer to a key that simplifies access to a restricted area. Regardless of the term used, skeleton keys continue to be an essential tool for locks and keys.