What is Tetraphobia?
[[Image:ShanghaiMissingFloors.jpg|thumb|160px|right|An [[elevator]] in [[Shanghai]] – floor numbers [[4]], [[13]] and [[14]] are missing]] '''Tetraphobia''' is a [[fear]] of the number [[4 (number)|4]]. It is a [[superstition]] found most often in [[East Asia]]n areas, for example [[China]], [[Japan]], [[Korea]], and [[Taiwan]].<ref>{{cite book |last=Havil |first=Julian | title=Nonplussed: Mathematical Proof of Implausible Ideas (Hardcover) |url=https://archive.org/details/nonplussedmathem00havi |year=2007 |publisher=Princeton University Press | isbn=978-0691120560 | page=[https://archive.org/details/nonplussedmathem00havi/page/153 153] }}</ref> The [[Chinese language|Chinese]] word for ''four'' ({{linktext|四}}, [[pinyin]]: sì, [[jyutping]]: sei<sup>3</sup>), sounds very similar to the word for ''death'' ({{linktext|死}}, [[pinyin]]: sǐ, [[jyutping]]: sei<sup>2</sup>). Chinese people take care not to use the number 4 during important holidays, or if someone in the family is sick. Numbers such as [[14 (number)|14]], [[24 (number)|24]], and so on, are not used because they also have the number 4 in them. Buildings sometimes do not have floors with these numbers, [[apartment]]s and hotels do not have rooms with number 4, 14, 24 and so on. Table number 4, 14, 24, may be often left out in [[wedding]] dinners or other social activities in these countries. Where there are a lot of apartment buildings, buildings that should be 4, 14, 24, are called 3A, 13A, 23A, and so on. In [[Hong Kong]], some apartments such as [[Vision City]]<ref>{{Cite web |url=http://www.visioncity.com.hk/notes_on_floor_plan_chi.html |title=Floor plan remarks of Vision City |access-date=2009-03-08 |archive-date=2007-07-18 |archive-url=https://web.archive.org/web/20070718143927/http://www.visioncity.com.hk/notes_on_floor_plan_chi.html |url-status=dead }}</ref> and [[The Arch (Hong Kong)|The Arch]]<ref>{{Cite web |url=http://www.thearch.com.hk/pdf/sky/sky_30th.pdf |title=Floor plan of The Arch |access-date=2009-03-08 |archive-date=2009-04-19 |arch