A locking device is a physical object used to secure an area or item. The three solutions for the term 'locking device' are HASP (4 letters), BOLT (4 letters), and COTTER (6 letters). A HASP is a metal loop with a hinged arm that is secured with a padlock. A BOLT is a metal rod with a head at one end that is inserted into a hole in a door or window frame and secured with a nut. A COTTER is a metal pin with a head at one end that is inserted into a hole in two pieces of metal to hold them together.