What does the phrase tat tvam asi mean?

The phrase “Tat tvam asi” is a Sanskrit expression from the Upaniṣhads, which means “You are that” or “That thou art.” It signifies the idea that the individual soul (Atman) is fundamentally the same as the ultimate reality (Brahman). This phrase highlights the concept of unity, suggesting that everything in the universe is interconnected and that one’s true self is not separate from the divine essence. It encourages self-realization and understanding that the individual is not different from the universal truth. This idea is central to Vedantic philosophy and spiritual awakening.

This question related to Chapter 7 Social Science Class 6th NCERT.
From the Chapter 7. India’s Cultural Roots.
Give answer according to your understanding.