'double-decker' originates from English, combining 'double' meaning 'twice as much' and 'decker' referring to a structure with multiple levels.

'double-decker' evolved from the concept of 'deck' in nautical terms, referring to the levels on a ship, and was adapted for use in vehicles.

Initially, it referred to ships with multiple decks, but now it commonly refers to buses and sandwiches with multiple layers.