A Grammar Lesson

The longest word in the english language is pneumonoultramicroscopicsilicovolcanoconoisis. It is 45 letters long (if it isn't then I've spelt it wrong) and it is a lung disease contracted by some miners.

The second longest is 39 letters long. It's hepaticocholangiocholecystenterostomies and it is 'the surgical creation of new communications between the intestines and the gall bladder'.

The next longest is floccipaucinihilipilification which is 29 letters long and means 'the action of estimating [something] as worthless'. It is a verb. I floccipaucinihilipilificate, you floccipaucinihilipilificate, he floccipaucinihilipilificates, we all floccipaucinihilipilificated.

The longest in "common" use are disproportionableness (21 letters), incomphrehensibilities (21 letters) and interdenominationalism (22 letters).

The longest word known to most people is antidisestablishmentarianism which is 28 letters long and it means 'opposition to the idea that the Church should cease to be formally recognized by the State'.

However

That is not all. The longest name in the world is the systematic name for DNA of the human mitochrondia containing 16,569 nucleotide residues and it is about 207,000 letters long!