firefly

noun fire·fly \ ˈfī(-ə)r-ˌflī \
Updated on: 4 Jan 2018

Definition of firefly

: any of various winged nocturnal beetles (especially family Lampyridae) that produce a bright soft intermittent light by oxidation of luciferin especially for courtship purposes

Recent Examples of firefly from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'firefly.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Illustration of firefly

First Known Use of firefly

1655


FIREFLY Defined for English Language Learners

firefly

noun

Definition of firefly for English Language Learners

  • : a small flying insect that produces a soft light


FIREFLY Defined for Kids

firefly

noun fire·fly \ ˈfīr-ˌflī \

Definition of firefly for Students

plural fireflies
: a small beetle producing a soft light


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