In Western superstition, what is the fear of the number 13 called?

In Western superstition, the fear of the number 13 is called triskaidekaphobia.

The term combines Greek roots meaning “fear” and “thirteen.” It describes an aversion to the number itself, rather than specifically to Friday the 13th. Some people avoid apartment, hotel, or airplane seat number 13, while some buildings omit a 13th floor in their numbering.

Triskaidekaphobia is often linked with the broader Western reputation of 13 as unlucky. The belief has several proposed historical associations, including the Last Supper’s traditional count of 13 people and older cultural concerns about unlucky numbers. However, no single origin explains every use of the superstition.

A common mix-up is with paraskevidekatriaphobia, which refers specifically to fear of Friday the 13th. The number 13 itself is the subject of triskaidekaphobia, whether or not it falls on a Friday.