It is Gerrys, and comes from the Ger part of the word Germany. It is just an informal term and a lot of British people do not use it.
In World War I the British called the Germans Jerry/Jerries although it was more commonly used in world war II.
Deutschland is what Germans call Germany. It translates as "Land of the Germans".
Germans
People who live in Germany are called Germans
They call them sinks.
During World War II, American soldiers had many names for their primary enemies. Italians were disparaged as "Eyeties", Germans as "Krauts" or "Nazis" or "Fritz" or "Jerries", and the Japanese as "Japs" or "Nips", among many other insulting or catchy nick-names.
Some people call them water waddles
The Germans refer to their flag as the Bundesflagge (Federal flag).
They are called "Swiss".
a tourch
Chips.
Some call it a sandwich others call it a 'buttie'.