first_class has definitions from the field of housing
1
[ noun ] the highest rank in a classification

Used in print

(Robert Heinlein, Stranger in a Strange Land....)

Mr._Booker_T._W._Jones_Food_Technician First_Class is not sad ; the Old_Ones have cherished him '' .

Related terms

superiority

2
[ noun ] mail that includes letters and postcards and packages sealed against inspection

Related terms

mail correspondence

3
[ noun ] (housing) the most expensive accommodations on a ship or train or plane

Related terms

accommodation

*