Triskadekaphophia is the official word for being afraid of Friday the 13th in any month.

How did the number thirteen become unlucky to some, while others consider the number to be lucky?

One theory in folklore posits that the unlucky number 13 originated with the Norse myth about 12 gods having a dinner party in Valhalla. The trickster god Loki, who wasn’t invited, arrived as the 13th guest, and arranged for Hoor to shoot Balder with a mistletoe-tipped arrow. Folklore historian Donald Dossey writes, “Balder died, the whole Earth became dark, the whole Earth mourned. It was a dark, unlucky day.” This major event in Norse mythology led to the number 13 to be considered unlucky. (It’s also the origin of the exclamation “balderdash,” but I digress…)

Another theory comes from the 1800s, when sources in England related the “unlucky” number thirteen to an idea that at the Last Supper, Judas, the disciple who betrayed Jesus, was the 13th to sit at the table, although the Bible doesn’t delineate the order in which the apostles took their seats.

In response to fear of thirteen, many hotels, ships, buildings and elevators have eliminated thirteen from their directories, instead skipping from twelve directly to fourteen to ease fears some people may have of the number 13.

And yet, some sports stars, including Wilt (the Stilt) Chamberlain, Dan Marino, Ozzie Guillen, and Alex Rodriguez all wore 13 as they tore through their respective sports (basketball, football, and baseball), setting records and making sports headlines throughout their careers.

Finland annually celebrates National Accident Day on a Friday the 13th to bring awareness to safety and decisions “made in haste.” Although not a national holiday, it’s an important way for the Finnish Ministry of Social Affairs and Health to bring attention to the hundreds of accidents involving pedestrians, bicycles, mopeds, and automobiles in the country.

How about you? Do you have triskadekaphobia? Will you be avoiding ladders, black cats, breaking a mirror, or other events that may bring you bad luck on this day or another Friday, the 13h? Or will you, like some of the athletes who sported the number on their backs, fly in the face of a number, and say, “It’s only superstition, only a number, I have bigger things to worry about!”

I hope it’s the latter, and that you have a hopeful weekend, with triskaidekaphobia in your rearview mirror.