ASL Sign Language Dictionary
Search and compare thousands of words and phrases in American Sign Language (ASL). The largest collection online.
How to sign: the highest region of the ionosphere (from 90 to 600 miles up) that contains the highest concentration of free electrons and is most useful for long-range radio transmission
Sorry, no video found for this word.
Similiar / Same: Appleton layer, F layer
Categories: part, region
Do you know the sign for this?
Upload your sign now.