means A state of calm stillness and peaceful repose, in mind or surroundings.

from From the Latin 'quietus,' meaning at rest or undisturbed — the same root that gives us 'quiet,' 'quit,' and even 'acquit' (to set free and leave in peace). It reached English through the Latin 'quietudo,' a noun of state, likely by way of French. The 'quietus' that meant final rest later picked up a darker shade — Shakespeare's Hamlet uses it for death itself, the ultimate stillness.