third class

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Accommodations, as on a ship or train, that are of the third and usually lowest order of luxury and price.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun US a reduced-rate mail service for printed matter
• noun UK formerly the cheapest accomodation on a train

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun inexpensive accommodations on a ship or train
• noun mail consisting of printed matter qualifying for reduced postal rates