noun
moon snail; moon shell
Refers to snails of the family Naticidae, known for their round shells.
海岸でタマガイの殻を拾った。
I picked up a moon snail shell on the beach.
noun
Akoya pearl oyster; Marten's pearl oyster
Specifically Pinctada fucata martensii, the oyster used for Akoya pearls. Cross-referenced with 阿古屋貝.
See also: 阿古屋貝
タマガイは真珠養殖に使われる。
The Akoya pearl oyster is used in pearl farming.
阿古屋貝 is a synonym for the Akoya pearl oyster (sense 2), while タマガイ can also refer to moon snails (sense 1).
The name タマガイ literally means 'jewel shellfish', from 玉 (たま, jewel) and 貝 (かい, shellfish). The exact historical derivation is uncertain.