Sri-bhagavan uvaca
yada viniyatam cittam
atmany evavatisthate
nisprhah sarva-kamebhyo
yukta ity ucyate tada
Meaning: When the yogi, by practice of yoga, disciplines his mental activities and becomes situated in transcendence-devoid of all material desires-he is said to be well established in yoga.
Bhagavad Gita: Well established in Yoga (Dhyana-yoga (Text 18 Ch 6))