What Is The Origin Of The Word "World"?
The ancient root of world meant ‘age or life of man’. The first part is the same as were- in werewolf (see wolf)—it means ‘man’—and the second part is related to old. The Anglo-Saxons first used world to mean ‘human existence, life on earth’ as opposed to future life in heaven or hell. America was first called the New World in 1555, and Europe, Asia, and Africa the Old World at the end of that century.
Olde worlde is a ‘fake’ antiquated spelling for old-fashioned things intended to be quaint and attractive, and dates only from the 1920s. The developing countries of Asia, Africa, and Latin America were initially known as the Third World in the 1950s by French writers who used tiers monde, ‘third world’, to distinguish the developing countries from the capitalist and Communist blocs. The first use in English came in 1963.
From Oxford Dictionary of Word Origins ?2010.