Triskaidekaphobia (from Greek tris meaning “3,” kai meaning “and,” and deka meaning “10″) is fear of the number 13; it is a superstition and related to a specific fear of Friday the 13th, called paraskevidekatriaphobia or friggatriskaidekaphobia.
The term would have been first used by I.H. Coriat in “Abnormal Psychology”,published in 1910, Moffat, Yard and company (New York). Library of Congress
There is a common myth that the earliest reference to thirteen being unlucky or evil is from the Babylonian Code of Hammurabi (circa 1780 B.C.E.), where the thirteenth law is omitted. In fact, the original Code of Hammurabi has no numeration.
Some Christian traditions have it that at the Last Supper, Judas, the disciple who betrayed Jesus, was the 13th to sit at the table. However, the number 13 is not uniformly bad in the Judeo-Christian tradition. For example, the 13 attributes of God (also called the thirteen attributes of mercy) are enumerated in the Torah (Exodus 34: 6-7).Some modern Christian churches also use 13 attributes of God in sermons.