Double-decker and Submarine sandwich

Double-decker noun - A vehicle carrying many passengers; used for public transport.

Submarine sandwich and double-decker are semantically related. In some cases you can use "Submarine sandwich" instead a noun phrase "Double-decker".

Submarine sandwich noun - A large sandwich made of a long crusty roll split lengthwise and filled with meats and cheese (and tomato and onion and lettuce and condiments); different names are used in different sections of the United States.

Double-decker and submarine sandwich are semantically related. You can use "Double-decker" instead a noun phrase "Submarine sandwich".