n. Fear of the number thirteen.
Composer Arnold Schoenberg, whose treatise on harmony was dedicated to "the hallowed memory of Gustav Mahler," developed a theory of writing music "using 12 tones" and perhaps as a result developed tridecaphobia — a trembling fear of the number 13.
Queen Saturn XIII, Cindy Larsen, rides atop her giant swan float as the 15-float parade rolls on Napoleon Avenue Wednesday. The parade's theme was 'Tridecaphobia,' which means fear of the number 13.
The more commonly accepted word for the fear of a baker's dozen is triskaidekaphobia (1911). However, I like tridecaphobia because it's much simpler to remember (and to spell!).