Syndication Exclusivity:

Syndication exclusivity (also known as syndex) is a federal law in the United States (Federal Communications Commission) designed to protect a local television station's rights to syndicated television programs by granting exclusive rights to the station for that program in the local market, defined by a station's Nielsen Designated Market Area. As a result, any airings of the same program on cable networks, outside market stations and superstations must be blocked by the local cable company or satellite carrier upon request from the local station.

Network Program Non-Duplication:

Network Program Non-duplication Rule allows a local TV broadcast station to protect it's exclusive distribution rights for network programming against duplicating programming carried on a nationally distributed superstation by a satellite carrier or outside market station on a cable system or satellite carrier.