Plionarctos is a word that refers to an extinct species of bear that lived in North America during the late Miocene epoch. While there are no synonyms for this particular word, there are several other terms related to this ancient animal. For example, it is a member of the Ursidae family, which includes all living and extinct bear species. Additionally, it is often referred to as a short-faced bear due to its distinct facial structure. Some other terms used to describe this species include Arctodus, which is another genus of short-faced bear, and the South American giant short-faced bear, which was a similar species that lived in South America during the same time period.