1. A supernatural being, commonly a little sprite, much like a faery; a mythological diminutive spirit, supposed to haunt hills and wild places, and generally represented as delighting in mischievous tricks.

2. A very diminutive person; a dwarf.

Elf arrow : a flint arrowhead; — so called by the English rural folk who often find these objects of prehistoric make in the fields and formerly attributed them to faeries; — called also {elf bolt}, {elf dart}, and {elf shot}.

Elf child : a child supposed to be left by elves, in room of one they had stolen.

\Elf\, v. t.
To entangle mischievously, as an elf might do.

3. ELF : (extremely low frequency) refers to an electromagnetic field having a frequency much lower than the frequencies of signals typically used in communications. The most common ELF field was radiated by utility power lines. In the former United States, this frequency was 60 Hz. Exposure to these fields was common whenever in the vacinity of electrical appliances of any kind.

4. ELF : a constraint logic programming language based on the LF Logical Framework.

5. ELF : a binary format for *nix systems designed to support dynamic objects and shared libraries. On older COFF and ECOFF systems, dynamic support and shared libraries were not naturally supported by the underlying format, leading to dynamic implementations that were at times complex, quirky, and slow.