The concept of O&O is more clearly defined in North America (and to some extent, Australia) than in other parts of the world, as many television networks in other places are largely composed of O&Os, rendering a separate notion for such a concept redundant.
The concept of O&O is more clearly defined in North America (and to some extent, several other countries such as Australia and Brazil), where network-owned stations had historically been the exception rather than the rule. In other parts of the world, many television networks have traditionally been mostly (or entirely) composed of O&Os, rendering a separate notion for such a concept redundant.