F-layer
noun
The highest and most strongly ionized region of the ionosphere.
Origin
1920s: arbitrary use of F + layer.
- rule of thumb
- rule-proving
- ruler
- ruler cult
- rulered
- ruleress
- rule-right
- rulering
- ruler joint
- rulership
- ruler-straight
- Rules
- Rules Committee
- ruleship
- rules-maker
- rule something out (or in)
- rule-staff
- rule the roost
- rule with a rod of iron
- ruling
- ruling class
- ruling elder
- ruling eldership
- ruling engine
- ruling grade