Film Term:
Exposure along the edge of the film from raw light, in most cases from a lightleak, due to the camera door not being taped. Edge Fog can sometimes be visible in the frame or sometimes outside of the frame effecting the clarity of the latent edge numbers.
Glossary of Film Terms - http://homepage.newschool.edu/~schlemoj/film_courses/glossary_of_film_terms/
reprinted with permission