also: かたがい
noun
Zoological term for a mollusk with a single shell, such as a snail or limpet. Contrasts with 二枚貝 (bivalve).
サザエは片貝の一種です。
The turban shell is a type of univalve.
片貝と二枚貝の違いを調べる。
I research the difference between univalves and bivalves.
Bivalve (two-shelled mollusk), while 片貝 refers to a univalve (single-shelled mollusk).
Compound of 片 (kata, 'one side') + 貝 (kai, 'shell'). The reading かたかい is a straightforward combination; the variant かたがい shows rendaku voicing.