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
Attendance at Fireflies home games is up nearly 40 percent, according to Baseball America.
Each photo where the firefly lights become trails is just one long exposure.
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.
First Known Use of firefly
FIREFLY Defined for English Language Learners
Definition of firefly for English Language Learners
: a small flying insect that produces a soft light
FIREFLY Defined for Kids
Definition of firefly for Students
: a small beetle producing a soft light
Seen and Heard
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