Reach:
In the application of statistics to advertising and media analysis, reach refers to the total number of different people or households exposed, at least once, to a medium during a given period of time. Reach should not be confused with the number of people who will actually be exposed to and consume the advertising, though. It is just the number of people who are exposed to the medium and therefore have an opportunity to see or hear the ad or commercial. Reach may be stated either as an absolute number, or as a fraction of a given population (for instance 'TV households', 'men' or 'those aged 25-35').
Frequency:
In the context of advertising, the number of times a person is exposed to an advertisement or the number of times an advertisement is repeated through a specific medium over a specific time period.
