i Register
In some senses, double-decker is marked as figuratively. Watch for register when choosing this word.
noun
A vehicle (usually a bus, coach or train) or aircraft with two floors.
A frigate with two decks above the waterline.
Any object with two layers or parts stacked on top of each other.
Any object with two layers or parts stacked on top of each other.
A headline that is two lines long.