This is the 5937th most frequent French word.
decker
"Decker" is not a French word.
Here, 'decker' is used as part of a compound word referring to the layers or levels of the bus.
Le bus à deux étages est appelé double-decker en anglais.
The two-story bus is called double-decker in English.
In this sentence, 'decker' again appears in a compound word, indicating the number of layers in the cake.
Ce pâtissier fabrique des gâteaux très élevés, parfois avec plusieurs étages, comme un triple-decker.
This pastry chef makes very tall cakes, sometimes with several layers, like a triple-decker.
Here, 'decker' describes the multi-story vehicles in the historical context of films.