Essential element definition: any chemical element required by an organism for healthy growth. It may be required in large amounts (macronutrient) or in very small amounts (trace element).

By definition, an essential element is one that is required for life and whose absence results in death. Because of the experimental difficulties involved in producing deficiencies severe enough to cause death, especially for elements that are required in very low concentrations in the diet, a somewhat broader definition is generally used.

essential element A chemical nutrient that is vital for the successful growth and development of an organism. Elements needed in relatively large amounts are termed macronutrients; those needed only in small or minute quantities are called micronutrients or trace elements.