1. The longest word in the OED (45 letters, 19
pneumonoultramicroscopicsilicovolcanoconiosis n [NL, fr. Gk pneumo-n + ISV ultramicroscopic + NL silicon + ISV volcano + Gk konis dust] : a pneumoconiosis caused by the inhalation of very fine silicate or quartz dust
2. hippopotomonstrosesquipedalian adj : pertaining to a very, very long word
From Mrs. Byrne's Dictionary of Unusual, Obscure, and Preposterous Words
3. floccinaucinihilipilification humorous. [f. L. flocci, nauci, nihili, pili; words signifying `at a small price' or `at nothing' enumerated in a well-known rule of the Eton Latin Grammar + -fication] The action or habit of estimating as worthless.
pronunciation:`flo.si.no-si. `ni.hili. pili.fi.`ka--sh*n
4. antidisestablishmentarianism [fr. anti- + disestablishmentarian + -ism.] Properly, opposition to the disestablishment of the Church of England(rare): but popularly cited as an example of a long word. So antidisestablishmentarian.
5. The longest word Shakespeare ever used:
honorificabilitudinity Obs. rare - 0. [ad. med.L. honorificabilitudinitas (Mussatus c 1300 in Du Cange), a grandiose extension of honorificabilitudo, honourableness
6. not too long, but a fun word, nonetheless:
om.pha.lo.skep.sis n [NL, fr. Gk omphalos + skepsis examination--more at spy] (1925): contemplation of one's navel as an aid to meditation; also: inertia 2
1983 Verbatim Summer 23/1
"Presumably, one arrives at game theory through omphaloskepsis."
7. deinstitutionalization Chiefly N. Amer. [fr. de- II. 2 + institutionalization] The process or action of removing (a person) from an institution, such as a mental hospital, or from the effects of institutional life.
1974 Science 2 Aug. 423/2
"A major current trend is toward deinstitutionalization. People who are down on jails believe that the institutional setting is too dehumanizing for any meaningful rehabilitation to take place."
8. supercalifragilisticexpialidocious a. Also supercalifragilistic; formerly also other varr. [Fanciful: cf. SUPER a. 3.] A nonsense-word used esp. by children, now chiefly expressing excited approbation: fantastic, fabulous.
1971 Daily Tel. 6 Nov. 13/5
If you can stand more than a day of supercalifragilisticexpialidocious entertainment you can settle in at the concrete Contemporary Resort Hotel.
9. Stewardesses is the longest word that is typed with only the left hand.
10. Homophony, monophony, and polyphony are the longest words typed with only the right hand.
11. Zoopharmacognosy is "the study of how animals medicate themselves. When animals are sick, they know what plants to eat to cure themselves." -- Eloy Rodriguez
12. Uncopyrightable is the longest word with no duplicate letters.
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