first class

Universal Words noun, adverb noun [U] 1 the best and most expensive seats or accommodation on a train, ship, etc: There is more room in first class. 2 (in Britain) the class of mail that is delivered most quickly: First class costs more. 3 (in the US) the class of mail that is used for letters and POSTCARDS 4 the highest standard of degree given by a British university adverb 1 using the best and most expensive seats or accommodation in a train, ship, etc: to travel first class 2 by the quickest form of mail: I sent the package first class on Monday.