What is essence? What is essence? The intrinsic or indispensable properties that serve to characterize or identify something.The most important ingredient; the crucial element.The inherent, unchanging nature of a thing or class of things. An extract that has the fundamental properties of a substance in concentrated form.Such an extract in a solution of alcohol.A perfume or scent.One that has or shows an abundance of a quality as if highly concentrated: a neighbor who is the essence of hospitality. Something that exists, especially a spiritual or incorporeal entity.in essence By nature; essentially: He is in essence a reclusive sort. of the essence Of the greatest importance; crucial: Time is of the essence.