#1st_class__1stclas__first_class__firstclas__first-class_mail__firstclassmail__1st-class_mail__1stclassmail__priority_mail  mail that includes letters and postcards and packages sealed against inspection
  supertype:  #mail  the bags of letters and packages that are transported by the postal service
  subtype:  #correspondence.1st_class__correspondence  communication by exchange of letters

No statement uses or specializes #1st_class; click here to add one.