first-class 1 adj. 1. Of the highest class or best kind; excellent; first-rate. Jane did a first-class job of repairing the coat. It was a first-class TV program.
Compare: TOP-NOTCH. 2. Of the best or most expensive class of travelling. Mr. Jones bought a first-class plane ticket to Chicago. 3. Belonging to the class of mail for sending letters, post cards, and handwritten or typewritten mail that is sealed. It is expensive to send a heavy letter by first-class mail.
first-class 2 adv. With the best material; in the best or most expensive way. When Mr. Van Smith goes anywhere he always travels first-class. "How did you send the package?" "First-class."