It's deeply ingrained in their culture.

Meaning

The tradition is a fundamental part of their society.

Examples

• John: Why do they celebrate the harvest festival this way?
• Alice: <b>It's deeply ingrained in their culture.</b> It's been passed down for generations.
• John: I see. It's very different from our traditions.
• Alice: Yes, it is. Their respect for nature is <b>deeply ingrained in their culture.</b>