an acronym for emissions of light and very low frequency perturbations due to electromagnetic pulse sources; extremely bright extremely short (less than a msec) electrical flashes forming a huge ring (up to 400 km diameter) in the ionosphere
"The satellite detected elves, which are brief electrical flashes that ripple across the upper atmosphere following a massive lightning strike."
plural of elf
"The forest was filled with elves dancing around the ancient oak tree during the winter solstice celebration."