Is the word Munchkin land in original Oz books?

No, the term "Munchkinland" is not found in the original Oz books written by L. Frank Baum. The concept of Munchkinland and the Munchkins themselves was introduced in the 1939 MGM musical film adaptation of "The Wonderful Wizard of Oz." In Baum's original works, the inhabitants of the land where Dorothy first encounters the Scarecrow, Tin Man, and Cowardly Lion were simply referred to as "the Munchkins."