Which term describes something that is existing or happening in many places?

The term that accurately describes something that exists or happens in many places is "widespread." This word conveys the notion of being broadly distributed or prevalent over a particular area or among various locations. When something is described as widespread, it indicates that it is not confined to a single area but rather is found in multiple places, showing its extensive reach or impact.

This term is often used in contexts such as the prevalence of a disease, the distribution of cultural phenomena, or the presence of certain species in various habitats, highlighting the important characteristic of being widely occurring. The essence of "widespread" directly correlates with the concept of broad diffusion across geographical or conceptual boundaries, making it the best choice for describing occurrences or entities that are found in multiple locations.