noun
whelk; sea snail (Neptunea, Buccinum)
Only with reading つぶ / ツブ
Refers to larger marine whelks, especially edible species. Often seen in seafood contexts.
北海道ではツブの刺身が名物だ。
In Hokkaido, whelk sashimi is a local specialty.
noun
small spiral-shelled snail; pond snail
Used for small freshwater or land snails with spiral shells. Less common than sense 1; often encountered in nature guides or traditional contexts.
See also: 螺 (にし)
田んぼで小さなツブを見つけた。
I found a small pond snail in the rice paddy.
Kanji compound is rare; the word is normally written in kana.
にし (螺) is an older or dialectal word for similar spiral-shelled snails, sometimes used in poetry or regional names. ツブ is the modern standard term.
The origin is uncertain. The word may be related to the shape or sound symbolism of small round objects, but this is speculative.