Quiescence

“Not permitting one thing to interfere with another is called "concentration". When the mind is asleep, it dreams. When it is relaxed, it moves of its own accord. When it is employed, it schemes. Therefore, the mind is never without movement. Nonetheless, there is still the capacity for quiescence. Not permitting dreams and petty annoyances to disrupt this capacity to know is called "quiescence".”

-- Xun Zi, ancient Chinese philosopher