1. In chemistry, the separation of one material from another one by washing: The processes of elutions can be done when a material contains water-soluble and water-insoluble materials so the passages of the solutions through the mixture will remove the portion that is water-soluble and leave the water-insoluble residue.
2. A method for removing materials from a mixture through washing, then decanting (separating the liquid from the sediment) by pouring off the fluid without disturbing the particles at the bottom: The chemist, Dr. Fergusson, performed an elution of materials by cleansing the pulverized substances and mixing them with water in order to separate the heavier elements which settle down in the solution from the lighter particles that are in the upper part of the liquid.