In the United States, stations are normally either "affiliates" or "independants". Affiliates are stations that are a part of a network. Most networks are nation-wide. Affiliates get much of the programs that they broadcast from the network. It is common for affiliates to broadcast the programs it gets from the network during the primetime hours of 8pm to 11pm and broadcast syndicated or local programing during the rest of the day. Local programing often includes local news, weather and traffic reports. Independant station are not a part of a larger network. They normally provide locally created or syndicated programs and movies.
For example, KTLA is the CW affiliate in Los Angeles. They broadcast programs that are provided to them by the national network The CW. It also broadcast locally created sports and news programs.