(Sanskrit सत्त्व) Literally, the essence, spirit, nature, entity, character of things. It can also be used to mean consciousness, embryo, fetus, demon, monster, goblin, noun, firmness, strength, reality, material or elementary substance, courage, vital breath, existence, quality of purity or goodness, good sense, strength of character, matter, disposition of mind, wisdom, being, resolution, life, animal, substantive, goodness, mind, energy, living being, self-command, living or sentient being.
Sattva is one of the three gunas, or qualities of nature. The quality of goodness, pleasure, clarity, serenity, illumination, detachment or purity. The “highest” of the three qualities.