The four elements of the mind in Yoga.
Buddhi – the intellect. Our ability to decide, discern, and discriminate.
Manas – the mind.
Citta – the unconscious mind, the seat of memory. It is the storehouse of all past impressions, past thoughts and experiences. The seat of our samskaras – either positive or negative. Samskaras are our psychological imprints.
Ahankara – the ego and self-identity.