CIMM DEFINITION: A term used to represent the average of a live rating for a (national) commercial minute and up to three days of DVR playback viewing.

2: Average Commercial Minute (ACM) rating that includes time-shifted viewing within 3 days (75 hours) of the live program telecast. (Source: Nielsen)

3: The average commercial second rating including live tuning to a  program plus 75 hours of DVR playback. (Source: TRA)