double-deck‧er /ˌdʌbəl ˈdekə◂ $ -ər◂/ noun [countable]

1. a bus with two levels ⇒ single-decker

2. a sandwich made with three pieces of bread and two layers of food
—double-decker adjective [only before noun]

[TahlilGaran] Dictionary of Contemporary English ▲

bus a large vehicle that people pay to travel on:
There were a lot of people on the bus.
coach British English a bus with comfortable seats used for long journeys:
Taking the coach is cheaper than the train.
minibus a small bus with seats for six to twelve people:
The school uses a minibus to take teams to matches.
double-decker a bus with two levels:
the red double-deckers in London
articulated bus (also bendy bus British English) a very long bus that has a joint in the middle that allows it to go around corners:
Articulated buses have been used in Europe for many years.
tram British English, streetcar American English, trolley/trolley car American English a vehicle for passengers, which travels along metal tracks in the street, and usually gets power from electric lines over the vehicle:
We waited at the stop for the tram.
San Diego has a well-used trolley system.

[TahlilGaran] English Thesaurus ▲