World's Longest Word

To determine the longest word in the world, was not an easy thing. because there are several different versions. starting from English dictionary version, Chemical term version, and Literature version,

Official english dictionary version
World's Longest Word in the english English dictionary version Pneumonoultramicroscopicsilicovolcanoconiosis. This word consists of 45 letters, Means Lung disease caused by inhaling crystalline silica dust. this word is the longest English word that appears in a major dictionary.

Chemical term version
Methionylthreonylthreonylglutaminylarginyl...isoleucine (total 189,819 letters). Is the chemical name for Titin, One of protein elements in humans body that work on the muscular elasticity system.

Literature version
In Literature version, the Longest Word is λοπαδο­τεμαχο­σελαχο­γαλεο­κρανιο­λειψανο­δριμ­υπο­τριμματο­σιλφιο­καραβο­μελιτο­κατακεχυ­μενο­κιχλ­επι­κοσσυφο­φαττο­περιστερ­αλεκτρυον­οπτο­κεφαλλιο­κιγκλο­πελειο­λαγῳο­σιραιο­βαφη­τραγανο­πτερύγων. This word is Greek language, means Name of foods made from a combination of fish, poultry and other meats.

Then, what is officially the longest word? The officially longest word is Pneumonoultramicroscopicsilicovolcanoconiosis (World's Longest Word in Official english dictionary version)