1. The highest region of the ionosphere (from 90 to 600 miles up) which contains the highest concentration of free electrons and is most useful for long-range radio transmission
   - F layer, F region

Type of: part, region

Part of: ionosphere

Encyclopedia: Appleton layer

• toffee-nosed
• toffy
• Tofieldia
• Tofieldia pusilla
• Tofranil
• toft
• tofu
• tog
• tog out
• tog up
• toga
• toga virilis
• Togaviridae
• together
• together with
• togetherness
• togged
• togged up
• toggery
• toggle
• toggle bolt
• toggle joint
• toggle switch
• Togo
• Togo franc