noun
ragworm; sandworm; clam worm
A type of marine polychaete worm, often used as fishing bait. The scientific genus is Hediste.
釣り餌にゴカイを使った。
I used ragworms as fishing bait.
干潟でゴカイを掘る。
Dig for ragworms on the tidal flat.
The origin is uncertain. The kanji 沙蚕 and 砂蚕 literally mean 'sand silkworm', describing the worm's habitat and appearance.