1. a stream that is the source or beginning of a river

Examples

• The headstream of the Mississippi River begins in northern Minnesota.
• Geologists traced the headstream to a small spring in the mountains.
• The headstream was barely a trickle during the dry season.
• Multiple headstreams converge to form the main river.
• The expedition followed the headstream to its origin.
• Pollution in the headstream affects the entire river system.