Here they are
The 45 letter word Pneumonoultramicroscopicsilicovolcanoconiosis is the longest English word that appears in a major dictionary.[4] Originally coined to become a candidate for the longest word in English, the term eventually developed some independent use in medicine.[5] It is referred to as “P45”.
Supercalifragilisticexpialidocious, at 34 letters, is a long English word that became famous after inclusion in a song sung by Julie Andrews and Dick Van Dyke in the Mary Poppins 1964 film.
Antidisestablishmentarianism, at 28 letters, is the longest non-coined, non-technical English word. It refers to a 19th century political movement that opposed the disestablishment of the Church of England as the state church of England.[citation needed]
Floccinaucinihilipilification at 29 letters (and meaning the act of estimating something as being worth so little as to be practically valueless, or the habit of doing so) is the longest non-technical, coined word in the English language.[citation needed]
Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch - is a village/community on the island of Anglesey in Wales. It’s the longest official place name in the UK at 58 letters. Turns out this name was created in the 1800’s to bestow the local railway station the honour of having the longest name of any railway station in Britain. Link to wiki here: [ame=“Llanfairpwllgwyngyll - Wikipedia”]Llanfairpwllgwyngyll - Wikipedia, the free encyclopedia[/ame]