1 – Pneumonoultramicroscopicsilicovolcanoconiosis (45 letters) :
Lung disease caused by the inhalation of crystalline silica dust.
2 – Hepaticocholangiocholecystenterostomies (39 letters) :
A surgical creation of a connection between the gall bladder and a hepatic duct and between the intestine and the gall bladder.
3 – Supercalifragilisticexpialidocious (34 letters) :
Something to say when you have nothing to say.
4 – Pseudopseudohypoparathyroidism (30 letters) :
A genetic disorder which closely imitates the indications but not the effects of pseudohypoparathyroidism and, thus it has mild or no manifestations of hypoparathyroidism or tetanic convulsions.
5 – Floccinaucinihilipilification (29 letters) :
Process of determining that something is absolutely valueless.
6 – Antidisestablishmentarianism (28 letters) :
Evolved in 1838 in Britain, it signifies opposition to proposals for the disestablishment of the Anglican Church.
7 – Honorificabilitudinitatibus (27 letters) :
This is the longest word ever applied by Shakespeare which stands for “The state of being able to achieve honours”.
8 – Radioimmunoelectrophoresis (26 letters) :
Immunoelectrophoresis (Electrophoresis to separate antigens and antibodies) using antigens or antibodies labeled with radioisotopes.
9 – Thyroparathyroidectomized (25 letters) :
The process of cutting out Thyroid and Parathyroid glands.
10 – Otorhinolaryngological (22 letters) :
Branch of medical science which deals with the treatment of head, neck, ear, throat and nose disorders.