 This does not quite offer a definition of “essence”, but rather defines what belongs to it. IId2 speaks of the essences of “things.” Individuals, or singular things, are surely things. If what belongs to the essence of an individual is given (by “given” Spinoza means “posited as existing”), then so too is the individual. This suggests that the essence of an individual is particular to that individual, since otherwise, what belongs to it could be given without that individual being posited, so long as some other individual with that essence were  posited.[12]