WordReference Random House Learner's Dictionary of American English © 2026
ˈfourth ˈclass, n. [uncountable]
WordReference Random House Unabridged Dictionary of American English © 2026- Stampsa class of mail consisting of merchandise weighing one pound or more and not sealed against inspection.
fourth′ class′,
fourth-class (fôrth′klas′, -kläs′, fōrth′-),USA pronunciation adj.
adv.
- Stamps(in the U.S. Postal Service) the class of mail consisting of merchandise weighing one pound or more, including parcel post and all first-, second-, or third-class matter weighing 8 oz. (227 g) or more and not sealed against inspection.
- 1860–65, American.
fourth-class (fôrth′klas′, -kläs′, fōrth′-),USA pronunciation adj.
- of, pertaining to, or designated as a class next below third, as for mailing, shipping, etc.
adv.
- Stampsas fourth-class matter;
by fourth-class mail:Send it fourth-class.
'fourth-class mail' also found in these entries (note: many are not synonyms or translations):