A railroad passenger car; especially, one of the luxurious ones named after the eponymous Pullman Palace Car Company
A Pullman is a type of train or railway carriage which is extremely comfortable and luxurious. You can also refer to a Pullman train or a Pullman carriage
A Pullman or a Pullman car on a train is a railway car that provides beds for passengers to sleep in. a very comfortable train carriage, or a train made up of these carriages (George M. Pullman (1831-97), U.S. inventor who designed the car;)