Diese beiden erlauben beide Schreibweisen :
1A device for connecting pieces of equipment that cannot be connected directly.
‘the adapter converts the lens focal length to 5.5 mm’
‘a tube fixed to the cleaner by means of an adapter’
1.1 A device for connecting several electric plugs to one socket.
2A person who adapts a text to make it suitable for filming, broadcasting, or the stage.
adapter noun [ C ] also adaptor uk /əˈdæp.tər/ us /əˈdæp.tɚ/
adapter noun [ C ] (DEVICE)
a type of plug that makes it possible to connect two or more pieces of equipment to the same electrical supply
a device that is used to connect two pieces of equipment