- the best, finest, or highest class, grade, or rank.
- the most expensive and most luxurious class of accommodation on trains, ships, airplanes, etc.
- (in the U.S. Postal Service) the class of mail consisting of letters, postal cards, or the like, together with all mailable matter sealed against inspection.
- the group receiving the highest distinction in an honors course.
- of the highest or best class or quality: a first-class movie.
- best-equipped and most expensive: a first-class railroad car.
- given or entitled to preferred treatment, handling, etc.: first-class mail.
- by first-class conveyance: to travel first-class.
- the class or grade of the best or highest value, quality, etc
- of the best or highest class or grade
- excellent; first-rate
- of or denoting the most comfortable and expensive class of accommodation in a hotel, aircraft, train, etc
- (in Britain) of or relating to mail that is processed most quickly
- (in the US and Canada) of or relating to mail that consists mainly of written letters, cards, etc
- education See first (def. 10)
- by first-class mail, means of transportation, etc