First class and First

First class noun - Mail that includes letters and postcards and packages sealed against inspection.

First and first class are semantically related. in prime topic. In some cases you can use "First" instead an adjective phrase "First class", when it comes to topics like best, top, superior, excellent.

First adjective - Coming before all others in time or order.

First class and first are semantically related. Sometimes you can use "First class" instead an adjective "First".

Nearby Word: firstly