first-class >> fəːst ˈklɑːs
Definition: [noun] a set of people or things grouped together as the best.
Example: he has created an orchestra of the first class
Definition: [adjective] of the best quality or in the highest grade.
Example: a stadium with first-class facilities
Definition: [adverb] using the best quality accommodation in a train or other form of transport.
Example: she flew first class from Miami to London