Absorption essences are basically what they sound like; a method/vehicle for absorbing the healing energy of the herb or holisticplant part. Flower essences and infused oils are absorption essences in their own right but in general an absorption essence refers to an essence made for external application or a bath additive. They are made like a flower essence but no alcohol is added and the essence is used fresh, in a manner that allows you to absorb the beneficial vibrations: as a wash, toilet water or skin tonic, bath or vaporized. Rose water and such are absorption essences.
Absorption essences are beneficial vehicles were the plant is not edible and an absolute oil is not readily available.