Etymologically a ‘Sesquipedalious’ word means a word one and half foot long.
Here are examples of some ‘sesquipedalious’ words.

1. Antidisesetablishmentarianism (28) – opposition to the disestablishment of the church of England.
2. Dicholorodifluoromethane (23) A type of Chlorofluromethane CF2C12
3. Floccinaucinihilipilification(29) – habit or the action of estimating something as valuless.
4. Hippopotomonstrosesquippedaliophobia (36)- Fear of long words.
5. Honorificabilitudinitatibus (27)- “the state of being able to achieve honours’. It is longest word in Shakespeare’s works having alternating consonants and vowels.
   6.Pneumonoultramicriscopicsilicovolcanoconiosis (45) – a lung disease.
   7.Pseudopseudohypoparathyroidism (30)– a mild form of thyrodism characterized
   By normal levels of calcium and phosphorus in blood.
   8. Thyroparathyroidectomized (25) Excision of both Thyroid and parathyroid glands.