[fawrth-klas, -klahs, fohrth-] /ˈfɔrθˈklæs, -ˈklɑs, ˈfoʊrθ-/
of, relating to, or designated as a class next below third, as for mailing, shipping, etc.
as fourth-class matter; by fourth-class mail:
Send it fourth-class.
(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 ounces (227 grams) or more and not sealed against inspection.
of or relating to mail that is carried at the lowest rate
by fourth-class mail
noun 1. “Remember the sabbath day, to keep it holy”: fourth of the Ten Commandments.
- Fourth cranial nerve
fourth cranial nerve n. See trochlear nerve.
noun 1. Physics, Mathematics. a dimension in addition to length, width, and depth, used so as to be able to employ geometrical language in discussing phenomena that depend on four variables: Time is considered a fourth dimension for locating points in space-time. 2. something beyond the kind of normal human experience that can be explained […]
- Fourth disease
fourth disease n. A mild exanthematous disease of childhood resembling scarlatina. Also called Dukes disease, scarlatinella.