Definition of audience rating in English:
audience rating
noun
US(In singular) a measure of the proportion of the total available audience tuned into a television channel, radio station, or programme at a particular time; (hence more generally) (assessment of) audience size or share (usually in plural).
Origin
1940s; earliest use found in Annals of the American Academy of Political and Social Science.
Are You Learning English? Here Are Our Top English Tips