Wikipedia
The concept of the First World originated during the Cold War and included countries that were generally aligned with or on friendly terms with the United States (including all NATO countries) and were generally identified as non-theocratic democracies with primarily market-based economies. While there is no current consensus on an exact definition of the term, in modern usage, "First World country" generally implies a relatively wealthy, stable and functional non-theocratic democracy with a reasonably well educated population, or just any developed country.
During the Cold War, relationships between the First World and the Second World of Communist states were typically competitive, ideological, and occasionally hostile. Relationships of both these "Worlds" with " Third World" countries (i.e. all the rest) were normally positive in theory, while some were quite negative in practice (such as proxy war between client states). Since the dissolution of the Soviet Union and advances in communication technology, relations amongst the "Worlds" are not as rigid, although there are still marked disparities, with the First World generally having more influence, wealth, and access to information and technological innovations than the Second and Third Worlds.
First World is a 2007 independent science fiction short film written and produced by Mark Lund and directed by Adam Starr. This 25 minute short has bypassed the traditional film festival circuit and has been distributed primarily at science fiction conventions in the United States, Japan, Australia and Great Britain. The short is based on a feature length screenplay of the same name and was primarily produced as a promotional tool to secure production of the long version of the story.
Usage examples of "first world".
There was old footage of the First World War, showing the artillery bombardments that preceded an attack and disembowelled bodies sprawled on the barbed wire.
It is found in the histories of the Toltecs that this age and 'first world', as they call it, lasted 1716 years.
Sir John had one splendid appearance in a play by a writer who had been a great figure in the theatre before and just after the First World War, but his time, too, had passed.
She couldn't help thinking of these evenings on their native planet, when he had tossed her in the air and kissed her or when he had brought gifts or when he had made his first world and come to visit before going to it.