赤貝

1. Origins, structure, and basic meaning

• Structure: 赤貝(あかがい) is the name of the shellfish known as a blood cockle.
• Basic usage: It is a noun for the shellfish, whether in a market tank or used as an ingredient.

2. Common pitfalls and similar expressions

• A name, not a color description
  • 赤い貝 describes a red shellfish, whereas 赤貝 names a particular kind. Not every red shellfish is an 赤貝.
• Shell and flesh
  • 赤貝の殻 refers to the shell rather than the whole shellfish. Distinguish it from 身, the flesh eaten as food.