Filosofian, esentzia izate edo entitate bati dagozkion beharrezko atributu eta ezaugarrien multzoa da, dagokion berezko izaera ez galtzeko nahitaezko dituenak.
Essence is a polysemic term, used in philosophy and theology as a designation for the property or set of properties that make an entity or substance what it fundamentally is, and which it has by necessity, and without which it loses its identity.