We were told in grammer school, before Google even was a dream, the longest real word in English was:
Antiestablismenttarianism
I only used Google to very my spelling.
Any other longer words break the rules. It was a real word that had a real purpose other that trying to be too long. This word was long recognized as the longest word.
Normally, English does not build long chain words as can be done in German.
And other word may be long, but not as long recognized, so not really the longest.
The rule is to count the number of letters and multiply by the square root of the number of years it has been recognized as a real long word. Go look it up. And not in Google. You must use a pre 1920 copy of the Britannica.
