Words of these nature are mostly invented and so we start off with Pneumonoultramicroscopicsilicovolcanoconiosis, which is a word with forty-five letters and is invented to describe a lung disease caused by inhalation of silica or quartz dust.
Hippopotomonstrosesquippedaliophobia: contains thirty-six letters and is used, surprisingly, to describe the fear of long words.
Supercalifragilisticexpialidocious: contains thirty four letters and is a word that is used as ‘something to say when you have nothing to say’.
Pseudopseudohypoparathyroidism: abbreviated as PPHP contains thirty letters, a word, which refers to an inherited disorder that closely simulates the symptoms but not the consequences of parathyroid hormone (low serum calcium and high phosphate), thus it has mild or no manifestations of hypoparathyroidism or tetanic convulsions.
Floccinaucinihilipilification: is twenty-nine letters long and is the act of regarding something as unimportant or without value and mainly used in humorous ways.
Antidisestablishmentarianism, which has twenty-eight letters is defined as any opposition to withdrawing government support of a church or religion.
Thyroparathyroidectomized: is a medical term that defines the removal of thyroid and parathyroid glands and consists of twenty-five letters.