snail; spiral shell
Refers to gastropods with a coiled shell, including both land snails and marine spiral shells. In everyday use, often points to the shell itself or the animal.
I picked up a beautiful spiral shell on the beach.
There was a small snail on a leaf in the garden.
sea snail
Standard kanji spelling with okurigana; common in news and general use.
Variant without okurigana; also seen but less common than 巻き貝.
A compound of 巻き “coiling, winding” and 貝 “shellfish,” with sequential voicing changing かい to がい.