masc. proper name, from Old French rousel, diminutive of rous "red," used as a personal name. See russet. Also a name for a fox, in allusion to its color. Compare French rousseau, which, like it, has become a surname. Russell's Paradox, "the set of all sets that do not contain themselves as elements," is named for Bertrand Russell (1872-1970) who is said to have framed it about 1901.