Why is the 4th-floor elevator button marked F?

In Korean, 4 is read "sa," which sounds the same as 死, the Chinese character meaning death. In Chinese, 4 (sì) and death (sǐ) differ only in tone and sound almost the same, and in Japanese, when 4 is read "shi," it also overlaps with the word for death. That's why a similar habit of avoiding 4 is common in all three countries.

Some hospitals in Japan have no room 4 or room 9, because 9 read as "ku" sounds the same as a word meaning suffering. In China, on the other hand, 8 is popular because it sounds like the word for making money. The 2008 Beijing Olympics opening ceremony began at 8:08 p.m. on August 8, a time chosen on purpose for that number.

The F floor isn't a missing floor; it's just the fourth floor with a different name. Some buildings don't even use F and label the button after 3 as 5, in which case the floor marked 5 is actually the fourth floor.

In the West, 13 is considered unlucky, so something similar happens. In 2002, a spokesman for the American elevator company Otis said that, based on the company's records, up to 85% of high-rise buildings don't use the name 13th floor. The floor after 12 becomes 14 or 12A. In Vancouver, Canada, one building dropped every floor containing a 4 as well as 13, so a tower with 53 floors was marketed as having 60.

Just changing a name isn't always harmless. When there's a fire, firefighters count floors from outside or move by the floor numbers, and if numbers are skipped, the floor a caller reports may not match the real height. On a smoke-filled staircase, that difference can slow down a rescue.

So from October 2015, the City of Vancouver required new buildings to number floors and units in order without skipping any. The rule didn't apply to buildings that already existed. If you ever need to tell someone where you are in an emergency, it's safer to also give the actual floor count from the bottom, not just the name on the button.