What Is Friggatriskaidekaphobia, or How Did Friday the 13th Get So Scary?

Fear of Friday the 13th affects 20 million people.

ByABC News
August 13, 2010, 2:25 PM

Aug. 13, 2010 -- Today is Friday the 13th, and whether you consider it to be the unluckiest day of the year, laugh in the face of superstition, or see it as an excuse to watch your favorite slasher movie, there's no denying that it's one of the calendar's most loaded dates.

But where does all the brouhaha surrounding Friday the 13th stem from?

Fear of Friday the 13th is suffered by approximately 17-21 million Americans, according to the Stress Management Center and Phobia Institute in Asheville, N.C. The phobia is referred to as friggatriskaidekaphobia, a 99-year-old word made up of a combination of the Norse and Greek roots words for 'Friday' (Paraskeví), '13' (dekatreís) and 'fear' (phobia).

As a great deal of superstitions and phobias stems from oral tradition, putting together their history is mostly guesswork. But for many centuries, 13 has been an unlucky number, while Friday has been considered the week's most unlucky day. Put these two together and the most superstitious minds will work overtime.

Traditionally in numerology, 12 is considered the number of completeness: the 12 signs of the zodiac, 12 hours of the clock, the 12 Apostles, the 12 tribes of Israel, the 12 days of Christmas – the list goes on. The number 13 is considered a transgression, or going beyond completeness.

Friday has been considered unlucky for a number of reasons, from the religious - Jesus was crucified on a Friday – to the financial. "Black Friday" has been associated with a number of stock market crashes. Frigga (Frigg) was a Scandinavian love goddess, worshipped on the sixth day of the week. Christians called Frigga a witch, and considered Friday to be the witches' day.

Today we see the widespread suspicion of the number 13 everywhere. The 13th floors are missing in many buildings, airports gate skip from 12 to 14, and the number 13 is left off of hotel rooms. Many athletes are hard-pressed to wear a 13 on their jersey. And in a deck of Tarot cards, the death card is the 13th card.