Waldo \wa(l)-do\ as a boy's name is pronounced WAL-doh. It is of Old German origin, and the meaning of Waldo is "rule". Short form and diminutive of a number of Old German names with the element Wald-, such as Oswald and Waldemar. Also possibly a German place name meaning "forest meadow". Literary: the "Where's Waldo" children books were popular in the 1990s, giving the name a somewhat comical connotation. Poet Ralph Waldo Emerson.