Broadcast delay

In radio and television, broadcast delay refers to the practice of intentionally broadcast of live material.

A short delay is often used to prevent profanity, bloopers, violence, or other undesirable material from making it to air, including more mundane problems such as technical malfunctions (i.e. an anchor's lapel microphone goes dead) or coughing. In this instance, it is often referred to as a seven-second delay or profanity delay.

Longer delays can also be introduced, often to allow a show to air at the same time for the local market as is sometimes done with nationally broadcast programs in countries with multiple time zones. That can sometimes be simply achieved with a video tape recorder or similar technology. In the context of modern digital video recorders, this can now be considered a class of time shifting. In this instance, it is often called a tape delay or west-coast delay in the United States, so-called because special events (including award shows) broadcast live in the Eastern or Central time zones of the US are often tape-delayed on the west coast. This includes Southern California (with the exception of the Academy Awards, which airs live in Los Angeles and the rest of the west coast), despite the fact that Southern California is where many live televised events (American Idol, Dancing With The Stars) take place. Nationally telecast morning news shows in the US (such as CBS This Morning, Today, and Good Morning America) typically are aired live only in the Eastern time zone, while on tape delay in the remaining time zones. This allows post-production staff to edit out any glitches that occurred during the live broadcast.

...
Wikipedia