means The human mind, soul, or spirit — the deep core of who you are, including all the conscious and unconscious stuff driving you.

from From Greek 'psyche,' meaning both 'soul' and 'breath' — the ancients linked the life inside you to the air leaving your lips, so the dying were said to breathe out their psyche. The same word named Psyche, the mortal woman beloved by Eros and made immortal, often pictured as a butterfly-winged maiden (the Greek word doubled as 'butterfly,' that fluttering emblem of the soul). It entered English in the 17th century as a poetic word for the soul, then got drafted into the modern vocabulary of the mind through 'psychology,' 'psychiatry,' and the rest of the psych- family.