# firefly

/ˈfaɪɝˌfɫaɪ/ (US) · /fˈaɪəflaɪ/ (UK) · CEFR B2 · Noun

Source: https://englishreference.com/word/firefly
Updated: 2026-05-08

## Definition

a small beetle that glows with a soft light in the dark. You usually see them flying around on warm summer nights.

For teachers: a nocturnal beetle of the family Lampyridae, characterised by the use of bioluminescence to attract mates or prey.

## Examples

- The children tried to catch a firefly in a glass jar.
- As the sun set over the meadow, hundreds of fireflies began to blink in the tall grass.
- The rhythmic flashing of the firefly is not merely decorative; it serves as a sophisticated species-specific signal used to locate potential mates in the dense evening foliage.

## Usage notes

- Commonly referred to as a 'lightning bug' in certain regional dialects of American English.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.