a pressrun, as that of a newspaper or magazine, which is interrupted after the running of a specified number of copies to permit the substitution of type or of a cut, as in a keyed advertisement: a device for testing the relative effectiveness of different versions of an advertisement.
SPLIT RUN
Meaning of SPLIT RUN in English
Random House Webster's Unabridged English dictionary. Полный английский словарь Вебстер - Random House . 2012