tetraphobia

thumb|upright|An elevator control panel in a residential apartment building in Shanghai with no floor numbered as the 4th thumb|The number 4 missing in a parking lot in Japan Tetraphobia () is the practice of avoiding instances of the digit number . It is a superstition most common in East Asian nations and is associated with death.

==Rationale== {| class="wikitable floatright" style="text-align:center;" !rowspan=2| Language !!colspan=2|Reading |- ! 四(four)!! 死(die) |- ! Proto-Sino-Tibetan | *b-ləj || *səj |- ! Old Chinese | /*s.lij-s/ || /*sijʔ/ |- ! Middle Chinese | /siɪH/ || /sˠiɪX/ |- ! Mandarin Chinese | sì || sǐ |- ! Shanghainese | sy² || shi², sy² |- ! Cantonese | sei³ || sei² |- ! Hakka | si³|| si⁴ |- ! Hokkien | sì, sù || sí, sú |- ! Vietnamese | tư, tứ || tử |- ! Korean | sa || sa |- ! Japanese | shi || shi |- |} The Chinese word for "four" (, pinyin: sì, jyutping: sei3) sounds quite similar to the word for "death" (, pinyin: sǐ, jyutping: sei2) in many varieties of Chinese. Similarly, the Sino-Japanese, Sino-Korean and Sino-Vietnamese words for "four", shi (し, Japanese), sa (사, Korean) and tứ or tư (Vietnamese), sound similar or identical to "death" in each language (see Korean numerals, Japanese numerals, Vietnamese numerals). Tetraphobia is known to occur in Korea and Japan (since the two words sound identical to each other in both languages), but not in Vietnam because the Sino-Vietnamese words have different tones to distinguish the two words and the native Vietnamese words for "four" and "death" are much more widely used than the Sino-Vietnamese equivalents in everyday language.