“Guna”is a Sanskrit word that represents the three qualities of nature, or types of energy.  The three qualities are:

Rajas: Comes from the root verb raj, which means “to glow.” It is a state of motion, vibrant, active, where the mind is overactive.

Tamas: Comes from the root verb tam, which means “to perish.”   It is a state of dullness, inertia, dormancy, where the mind is underactive.

Sattva: Comes from the root sat, meaning “being.” This is a state of beingness, where there is nothing to do, no desire, just light and bliss.  Sattva is a balance of rajas and tamas that is purity, harmony and lightness.