1. an area of land that drains water into a particular river, lake, or ocean
2. a ridge of high land dividing two areas that are drained by different river systems
3. an important point of division or transition; a turning point

Examples

• The Mississippi River watershed covers about 40% of the continental United States.
• Rain falling on either side of the watershed flows into different river systems.
• The Rocky Mountains form a major watershed between eastern and western drainage.
• The invention of the internet was a watershed moment in human communication.
• Her graduation marked a watershed in her life.
• The company’s bankruptcy was a watershed event for the entire industry.
• Scientists study how pollution affects the local watershed.
• The Continental Divide is North America’s most significant watershed.