What is the Longest Word in English?

I found various sources with contradictions in which word is the longest English word. The following words came from a book called THE TOP 10 OF EVERYTHING by Russell Ash. The criteria for being included in this list of longest words was that the words had to have appeared in some other printed material and were not just invented for the sole purpose of being the longest word. The Guinness Book of Records lists other words as being the longest; however, these words are chemical compounds and have never been used in print. Here's the list of the 10 longest words:

(# 5 is usually considered to be the longest word in a quiz.)

1. This word has 1,185 letters. It is a chemical compound for the Tobacco Mosaic Virus, Dahlemense Strain. It appeared in print in the American Chemical Society’s Chemical Abstracts. Some people do not consider chemical compounds fair to include in the longest word list because such words can be created by linking together scientific names of their components. Here we go -- I hope I spell it correctly!!

acetylseryltyrosylserylisoleucylthreonylserylprolylserylglutaminylphenylalanylvalylphenylalanylleucylserylserylvalyltryptophylalanylaspartylprolylisoleucylglutamylleucylleucyllasparaginylvalylcysteinylthreonylserylserylleucylglycllasparaginylglutaminylphenylalanylglutaminylthreonylglutaminylglutaminylalanylarginylthreonylthreonylglutaminylvalylglutaminylglutaminylphenylalanylserylglutaminylvalyltryptophyllysylprolylphenylalanylprolylglutaminylserylthreonylvalylarginylphenylalanylprolylglycylaspartylvalyltyrosyllsyslvalyltyrosylarginyltyrosylasparaginylalanylvalylleucylaspartylprolylleucylisoleucylthreonylalanylleucylleucylglycylthryonylphenylalanylaspartylthreonylarginylasparaginylarginylisoleucylisoleucylglutamylvalylglutamylasparaginylglutaminylglutaminylserylprolylthreonylthreonylalanylglutamylthreonylleucylaspartylalanylthreonylarginylarginylvalylaspartylaspartylalanylthreonylvalylalanylisoleucylarginylserylalanylasparaginylisoleucylasparaginylleucylvallasparaginylglutamylleucylvalylarginylglycylthreonylglycylleucultyrosylasparaginylglutaminylasparaginylthreonylphenylalanylglutamylserylmethionylserylglycylleucylvalyltryptophylthreonylserylalanylprolylalanylserine

2. This word has 182 letters. This is the English transliteration of a 170 letter Greek word that appears in THE ECCLESIAZUSAE by the Greek playwright Aristophanes. It is a description of a 17 ingredient dish.

aopadotenachoselachogaleokranioleipsanodrimhipotrimmatosilphioparaomelitokatakechymenokichlepikassyphophattoperisteralektryonoptekephalliokigklopeleiolagoiosiraiobaphetraganopterygon

3. This word has 52 letter. It was invented by Dr. Edward Strother to describe the spa waters at Bath.

aequeosalinocalcalinosetaceoaluminosocupreovitriolic

4. This word has 51 letters. Created by writer Thomas Love Peacock, this word describes the structure of the human body in his satire HEADLONG HALL.

asseocarnisanguineoviscericartilaginonervomedullary

5. This word has 45 letters. This is a lung disease caused by breathing very fine dust. Some people consider this to be the longest word because it has been included in Webster’s Dictionary and the Oxford English Dictionary.

pneumonoultramicroscopicsilicovolcanoconiosis

6. This word has 39 letters. These are surgical operations to create channels of communication between gall bladders and hepatic ducts or intestines.

hepaticocholangiocholecystenterostomies

(7 & 8 is a tie. Each of these words has 34 letters)
7. This word means the false opposition to the withdrawal of state support from a Church.

pseudoantidisestablishmentarianism

8. This word was popularized by Mary Poppins to mean wonderful and has since been listed in the Oxford English Dictionary. supercalifragilisticexpialidocious

(9, 10 & 11 are a tie: Each of these words has 30 letters)

9. The name of a syndrome caused by a virus associated with encephalitis.

encephalomyeloradiculoenuritis

10. This word means pertaining to an extremely long word.
hippotomonstrosesquipedalian

11. This is used to describe a case in which a patient appears to have symptoms of pseudohypoparathyroidism but no manifestations suggesting hypoparathyroidism.

pseudopseudohypoparathyroidism

12. The word meaning to go against the government has 27 letters.
antiedisestablishmenteryism