Meanings
The three (in England) estates were originally the three classes of people who could participate in government, either directly or by electing representatives – originally the clergy, barons/knights, and the commons (though they changed over time). Later the "three estates" were misunderstood as being the three governmental powers necessary for legislation: the Crown, the House of Lords, and the House of Commons; from there, the idea of a "fourth estate" was often used in satirical or jocular expressions, before developing a fixed association with the Press.
How to pronounce "fourth estate":
A hypothetical fourth class of civic subjects, or fourth body (in Britain, after the Crown, and the two Houses of Parliament) which governed legislation.
Journalism or journalists considered as a group; the press.
