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.