1. narrow bands of strong, fast-moving winds in the upper atmosphere, typically at the boundaries between warm and cold air masses
Usage: usually plural or used as singular 'jet stream'; meteorology term

Examples

• Jetstreams in the upper atmosphere can reach speeds of over 200 miles per hour.
• The polar jetstream influences weather patterns across North America.
• Pilots often use jetstreams to reduce flight times on long-distance routes.
• Climate scientists study how jetstreams are shifting due to global warming.
• The subtropical jetstream typically flows over the southern United States during winter.