Impressions
Also known as: Ad impressions, Views
An impression is a single instance of an ad being displayed. Impressions count views, not unique people or clicks.
Impressions count how many times your ad was shown, including repeat views to the same person. They differ from reach (unique people) and frequency (average views per person): Impressions ≈ Reach × Frequency. Awareness campuses are often priced by impressions via CPM.