(in the U.S. Postal Service) the class of mail consisting of merchandise weighing up to 16 ounces, and written or printed material, as books, manuscripts, or circulars, not sealed against postal inspection.
the lowest of three honors degrees conferred by a British university.
Origin of third class
[thurd-klas, -klahs] /ˈθɜrdˈklæs, -ˈklɑs/
of the lowest or poorest class or quality; inferior.