Antidisestablishmentarianism:
The term originated in the context of the nineteenth century Church of England, where "antidisestablishmentarians" were opposed to proposals to remove its status as the state church of England. Antidisestablishmentarianism succeeded in England, but failed in Ireland and Wales, with the Church of Ireland being disestablished in 1871 and the Church in Wales in 1920. The term has largely fallen into disuse, although the issue itself is still current (see Act of Settlement 1701).
The word antidisestablishmentarianism, with 28 letters, is often quoted as being one of the longest English words that has an actual meaning (as opposed to words that were made up for the purpose of being long). In fact, its claim is quite good, since antidisestablishmentarianism is used seriously in academic and ecclesiastical writing about the Church of England when the concept arises, which it does occasionally