A larval form of a gnat or a small worm-like creature resembling or related to gnats.
Compound word: gnat + worm. Both Old English words combined to describe the larval stage of gnats, which are worm-like before becoming the winged adult insects.
Gnatworm shows that people were curious enough about insect life cycles to name the larval stage separately—this was important before microscopes, when farmers needed to identify what was eating their crops!
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