glowworm

US: /ˈgloʊˌwɝm/ ,(glō′wûrm′)

WordReference Random House Learner's Dictionary of American English © 2025

glow•worm /ˈgloʊˌwɜrm/   n. [countable]

1. Insects the wingless female of a beetle, which gives off a continuing greenish light. Compare firefly.

WordReference Random House Unabridged Dictionary of American English © 2025

glow•worm  (glō′wûrm′), n. 

1. Insects the wingless female or larva of the European beetle, Lampyris noctiluca, which emits a sustained greenish light.
2. Insects any of various other beetle larvae or wingless females that emit a glow rather than a flash of light.

• Middle English. See glow, worm 1300–50

Collins Concise English Dictionary © HarperCollins Publishers::

glow-worm noun

1. a European beetle, Lampyris noctiluca, the females and larvae of which bear luminescent organs producing a greenish light: family Lampyridae

See also firefly1