Glossary of Common Television Terms:

Certificate of performance - Station invoices for spot TV time include an affidavit attesting to the fact that the commercials were run at the times agreed upon.

Closing Date - The date when specified materials must be received by a TV station.

Rating - The estimated percentage of all TV household or persons tuned into a specific station.

Reach - The estimated number of unduplicated or different household or persons that watched a specific station at least once for five minutes during the average week of the reported time period.

Rotation, Horizontal - Buying TV air time every day of the week during a specific time.

Rotation, Vertical - Buying TV airtime more than once on the same program.

Share - The estimated percent of all households watching TV.