turtle

1. Origins, structure, and basic meaning

• Structure: 亀 means a turtle and is read かめ as a standalone word.
• Basic usage: 海亀, read うみがめ, means a sea turtle; in this compound, かめ changes to がめ.

2. Common pitfalls and similar expressions

• A compound with a different reading
  • 亀裂, read きれつ, means a crack or rift.
  • It does not retain the animal name's reading かめ.
• A physical crack and a damaged relationship
  • 壁に亀裂が入る describes a wall cracking; 信頼関係に亀裂が入る figuratively describes damage to a relationship of trust.
  • In a relationship, it describes worsening relations rather than a physical gap.