From Wikipedia:

The fear of Friday the 13th has been called black friday (Frigga being the name of the Norse goddess for whom "Friday" is named and triskaidekaphobia meaning fear of the number thirteen), or paraskevidekatriaphobia a concatenation of the Greek words Paraskeví (meaning "Friday"), and dekatreís (meaning "thirteen") attached to phobía (meaning "fear"). The latter word was derived in 1911 and first appeared in a mainstream source in 1953.