Reach

Reach

a dis-aggregated number of people (or percentage of an audience) that have been exposed to content. ‘Reach’ differs from impressions, opportunities to see and eyeballs in that it counts the actual number of people exposed to coverage rather than the number of ‘opportunities’ to see the coverage. It is a widely mis-used term in the industry and should only be used when readership data has been dis-aggregated to take account of cross readership patterns.
(Source: www.amecorg.com, June 13, 2012)