The term 'Locked Door Opener' is a job description for a KEY, which is an object with three letters. A KEY is used to open a locked door, and it is usually made of metal or plastic. It has a unique shape that fits into the lock mechanism, allowing the door to be opened. Keys are also used to secure other items, such as cabinets and safes. Keys are an important part of security, as they provide access to restricted areas and protect valuable items from theft.