ELF
WordNet
noun
(1) Below 3 kilohertz
(2) (folklore) fairies that are somewhat mischievous
WiktionaryText
ELF
- Extremely low frequency, the band of radio frequencies from 3 to 30 hertz
- Executable and Linking Format, a common object file format for Unix
- Earth Liberation Front (radical environmentalism group)
- Elvish Linguistic Fellowship, an organization that studies the invented languages of J. R. R. Tolkien
- Endangered Language Fund, a non-profit organization