Trapdoors are a type of door that opens by being lifted or pulled downwards. There are several synonyms for trapdoors including hatches, flaps, ports, doors, and covers. Hatches are typically found on boats or ships and can be used as an entrance or exit to the vessel's hull. Flaps are often used in the aviation industry to grant access to different parts of an airplane. Ports are a type of trapdoor that can be found on submarines, allowing for diversified usage. Doors and covers are more general terms used to describe any type of trapdoor. Regardless of the term used, the purpose of all trapdoors remains to provide a discreet or temporary entrance or access point.