Film Term:
A set of sync marks on picture and sound that line up at the same frame, as opposed to printer’s sync, where the picture and sound are displaced. Sometimes it is usedful to label a sync mark E.S. to know that it is an editorial sync mark.
Glossary of Film Terms - http://homepage.newschool.edu/~schlemoj/film_courses/glossary_of_film_terms/
reprinted with permission