# firefly

> English word · Noun · IPA /ˈfaɪ.əˌflaɪ/ · frequency rank #24,447

## Definitions
1. Any beetle of the family Lampyridae, which exhibit bioluminescence during twilight.

## Etymology
Endocentric compound of fire + fly, because the insects glow; whence also lightning bug. Compare glow fly, glowworm, and lanternfly.

## Easily confused with
- **freely** (https://plainspell.com/en/vs/firefly-vs-freely)
- **firmly** (https://plainspell.com/en/vs/firefly-vs-firmly)
- **firstly** (https://plainspell.com/en/vs/firefly-vs-firstly)
- **Firefox** (https://plainspell.com/en/vs/firefly-vs-firefox)
- **finely** (https://plainspell.com/en/vs/finely-vs-firefly)

## Common misspellings (11)
`ffirefly`, `fierfly`, `fireffly`, `fireflly`, `fireflyy`, `firefyl`, `firelfy`, `firfely`, `firrefly`, `friefly`, `ifrefly`

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/firefly