Meaning of the word "deep sleep" in English

What does "deep sleep" mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

deep sleep

US /diːp sliːp/
UK /diːp sliːp/

Noun

the deepest stage of sleep, characterized by slow brain waves and minimal physical activity, during which the body and mind undergo significant restoration

Example:
After a long day, I fell into a state of deep sleep.
The baby was in such a deep sleep that nothing could wake him.