13 (number)

13 (thirteen /θɜrˈtiːn/) is a natural number after 12 and before 14. It is the smallest number with eight letters in its name spelled out in English.

In speech, the numbers 13 and 30 are often confused. When carefully enunciated, they differ in which syllable is stressed: 13 i/θərˈtiːn/ vs. 30 /ˈθɜrti/. However, in dates such as 1300 ("thirteen hundred") or when contrasting numbers in the teens, such as 13, 14, 15, the stress shifts to the first syllable: 13 /ˈθɜrtiːn/.

Strikingly similar folkloric aspects of the number 13 have been noted in various cultures around the world: one theory is that this is due to the cultures employing lunar-solar calendars (there are approximately 12.41 lunations per solar year, and hence 12 "true months" plus a smaller, and often portentous, thirteenth month). This can be witnessed, for example, in the "Twelve Days of Christmas" of Western European tradition.