What is the differences between watershed and tributary?

A watershed is a land area that directs rainwater and snowmelt to a common body of water, such as a river or lake, acting as a natural drainage system. In contrast, a tributary is a smaller stream or river that flows into a larger river or body of water. While watersheds encompass entire regions that collect and funnel water, tributaries are specific watercourses that contribute to the flow of a larger waterway. Essentially, all tributaries are part of a watershed, but not all parts of a watershed contain tributaries.