first class

Short definition from Wiktionary

Adjective

1. 1
   Belonging to the best or top group in a system of classification.
2. 2
   Of, or relating to the most luxurious and expensive class of accommodation on a train, ship, hotel, etc.
3. 3
   Of, or relating to a class of mail to be delivered before second class.
4. 4
   Great, very enjoyable.
5. 5
   Of or relating to a first class match.
6. 6
   Of or relating to a treatment like that for a first-class object.
7. 7
   Alternative form of first class.

Noun

1. 1
   premier rank.
2. 2
   The third year of primary school, following after the junior and senior infant levels.
3. 3
   One of two classes of city government in the U.S. state of Kentucky, in which cities elect a mayor and aldermen.