It can be a rebroadcast or a repeat.
noun (Broadcasting) a television or radio programme that is shown or put on again
From Collins. The word rebroadcast tends to imply that the original broadcast was live. The editing might reflect that. The word "rebroadcast" can also be used as a verb, e.g.
The final is on live now, but it’ll be rebroadcast tomorrow afternoon.
You might also see it at the start of a (pre-recorded) topical show, or one that contains time dependent data. For example, some of the property shows which have details of house prices might be preceded with "This show was originally broadcast in September 2014".
And a "repeat" is simply the same show repeated, regardless of whether it was originally live or pre-recorded.